HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369D/E/FF-500/600N HELICOPTERS (ISSUED: 1990)

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(5). Secure oil cooler outlet duct to oil cooler

replenish transmission with oil lost

with four bolts, washers and nuts.

(Ref. Sec. 12-00-00).

(6). Install tee (with drain cap), elbow and

10. Main Transmission Oil Pressure Sender

tubes that run from oil cooler to oil

Replacement

cooler bypass valve housing, applying

light coat of antiseize compound

(Ref. Figure 404) The main transmission oil

(CM112) to threads.

pressure sender provides a ground to cause the

XMSN OIL PRESS warning light to illumi

(7). Install oil drain tube and fitting on tee.

nate when oil Pressure is low. It also provides

a ground to the running-time meter. Sender's

(8). Install compressor cooling duct.

normally-closed contacts open when oil

pressure increases to 15 ±2 psi (103 ±14 kPa);

simultaneously the sender's normally-open

(9). Fill main transmission lubrication

contacts close.

system (Ref. Sec. 12-00-00).

9. Main Transmission Oil Temperature

Consumable Materials

Sender Replacement

(Ref. Section 91−00−00)

Item

Nomenclature

(Ref. Figure 404) The oil temperature sender

CM112

Anti-seize compound high temperature

for the main transmission lubrication system

CM726

Tape, teflon

is installed in a housing inserted in the 1/2

inch oil line to IN port of lubrication pump.

Switch contacts close when oil temperature

(1). Detach electrical wire or wires and

exceeds 240° ±l0°F (116° ±5°C).

using absorbent cloth, unscrew sender

from transmission.

Consumable Materials

(2). Apply light coat of antiseize compound

(Ref. Section 91−00−00)

(CM112) or wrap two or three turns of

Item

Nomenclature

teflon tape (CM726) on tapered threads

CM112

Anti-seize compound high temperature

of sender. Screw in sender; torque to 30

CM726

Tape, teflon

- 40 inch-pounds (3.39 - 4.52 Nm).

Connect wire; make sure that connec

tion is clean and tight. If three wires

are present, for information on connec

(1). Remove lockwire and detach electrical

tion of third wire refer to wiring

wire from sender terminal post.

diagram for running time meter.

Position container for draining trans

mission oil cooler line. Remove two set

screws securing sender within sender

11. Liquid Level Plug Replacement

housing. Unscrew sender and drain oil

(1). Drain oil from transmission until oil

in container. Plug housing to prevent oil

level is well below edge of plug port

drainage.

(Ref. Sec. 12-00-00).

(2). Apply a light coat of antiseize com

(2). Remove safetywire from plug.

pound (CM112) or tightly wrap two or

three turns of teflon tape (CM726) on

(3). Remove plug by unscrewing counter

tapered threads of sender. Screw

clockwise.

temperature sender into housing;

torque to 30 - 40 inch-pounds (3.39 -

(4). Remove and discard O-ring. Install

4.52 Nm). Install set screws until light

new O-ring on plug.

contact is made with sender. Lockwire

hex of sender to drilled head of ground

(5). Install plug by screwing clockwise.

wire screw in sender housing. Connect

Torque plug to 80 - 90 inch-pounds

electrical wire to sender terminal and

(9.04 - 10.17 Nm); install safetywire.

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

BREATHER-FILLER

SPLINES FOR

O-RING

MAIN ROTOR

(NOTE)

DRIVE SHAFT

OUTPUT SHAFT

(TAIL ROTOR)

OIL SEAL

OIL PRESSURE

SENDER

COOLING BLOWER

MOUNTING BRACKET

CHIP DETECTOR

AND SELF-CLOSING

DRAIN VALVE

COOLING BLOWER

PULLEY SPACER

CHIP DETECTOR

INPUT SHAFT

SELF-CLOSING

DRAIN VALVE

NOTE:

INPUT SHAFT SEAL

O-RING MUST BE CEMENTED IN PLACE

DRAIN CONNECTOR

BEFORE INSTALLING TRANSMISSION.

63-2001

Figure 404. Main Transmission − Cross−Section View

12. Chip Detector Replacement

belt. The blower exhausts air through the

engine oil cooler and the main transmission oil

(Ref. Figure 404) For removal and installation

cooler. Exhaust air from transmission and

instructions, refer to Draining Main Transmis

engine oil coolers is directed at various

sion (Ref. Sec. 12-00-00). For functional test

external portions of the engine and engine

information for detector circuit, refer to Sec.

accessories.

95-30-00.

B. Cooling Blower Removal

13. Cooling Blower Replacement

(Ref. Figure 405)

A. Cooling Blower

(1). Remove main transmission drive shaft

(Ref. Figure 405) The cooling blower is

and blower access door.

mounted to a bracket on the aft underside of

(2). Remove coupling bolt, coupling, shim(s)

the main transmission and coupled to the

and pulley from transmission input

transmission input shaft by a pulley-driven

shaft.

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CSP-HMI-2

MAINTENANCE MANUAL

(3). Disconnect cooling blower drain tube.

In the following step do not use

CAUTION

Loosen tie-down straps on blower duct

levers or other tools on belt, or

rubber connectors and roll back

in any way force belt onto pulley.

connectors to disconnect ducts from

(5). Slide pulley onto transmission input

cooling blower.

shaft to engage belt in teeth of both

(4). Cut lockwire and remove four bolts

attaching mounting bracket to trans

pulleys.

mission. Remove two shims inserted

(6). Adjust belt tension.

between bracket and transmission pad.

NOTE: Instructions in step (7). below, apply

(5). Remove mounting bracket (with blower,

only when original shim(s) (same shim

pulley and belt) from helicopter.

thickness) are installed and drive shaft,

NOTE: For 369D25100 transmission installa

overrunning clutch and couplings remain

tion only; If equipped with 369D25626-11

unchanged. A distance of 0.010 inch (0.254

mount bracket, examine bolts securing

mm) between bolt seating surface on cou

mount bracket to cooling blower assembly. If

pling and transmission input shaft is re

safety wired, remove and discard bolts. Re

quired to ensure coupling bolt will not bot

place with NAS1224-1L self-locking bolts.

tom out shaft and to provide proper

(6). Disassemble cooling blower if required.

assembly clamp up. (Ref. Sec. 63-10-00).

C. Cooling Blower Installation (369D25100

The 0.010 inch (0.254 mm) mini

CAUTION

Transmission)

mum measurement between the

(Ref. Figure 405)

bolt seating surface and the input shaft

must be obtained to ensure proper clamp up.

(1). Install pulley guard on main transmis

Warped shims or foreign material could pro

sion input shaft.

(2). With belt looped around transmission

vide a false 0.010 inch (0.254 mm) minimum

input shaft, position mounting bracket

measurement and improper clamp up could

on main transmission pad and loosely

result during normal operation which may

install four bolts and washers. Before

damage the main transmission input shaft.

tightening bolts, insert two shims

(7). Install laminated shim and coupling on

between bracket and transmission pad.

transmission input shaft. Secure

Verify that blower scroll clears tail rotor

coupling with coupling bolt; torque to

drive shaft by at least 0.190 inch (4.83

mm). Torque bolts to 65 - 75 inch-

250 - 300 inch-pounds (28.25 - 33.90

pounds (7.34 - 8.47 Nm). Lockwire

Nm) plus drag torque.

bolt heads after belt tension is checked.

(3). Connect drain tube to cooling blower

(8). Make sure belt tracks correctly (Ref.

scroll fitting. Clamp tube to fitting with

Cooling Blower Belt Tracking).

two turns of lockwire.

(4). Roll exhaust duct rubber connectors

(9). Install main transmission drive shaft

onto scroll outlets and secure with

(.Ref Sec. 63-10-00).

tie-down straps (Transmission oil

cooler duct and engine oil cooler duct).

(10). Install access panels.

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CSP-HMI-2

MAINTENANCE MANUAL

D. Cooling Blower Installation (369F5100

In the following step, do not use

CAUTION

Transmission)

levers or other tools on belt, or

in any way force belt onto pulley.

(Ref. Figure 406)

(6). Slide driver pulley onto transmission

Consumable Materials

input shaft to engage belt in teeth of

(Ref. Section 91−00−00)

both pulleys.

Item

Nomenclature

The minimum of 0.010 inch

CM111

Grease, aircraft

CAUTION

(0.254 mm) measurement be

CM112

Anti-seize compound high temperature

tween the bolt seating surface and the input

CM425

Sealing compound

shaft must be obtained to ensure proper

CM702

Lockwire CRES

clamp-up.

(1). With belt looped around driven pulley,

D Warped shims or foreign material could

install oil cooler fan bracket.

provide a false 0.010 inch (0.254 mm)

minimum measurement and improper

NOTE: NAS1304 series bolts may be used in

clamp-up could result, which during nor

place of NAS6604 series bolts.

mal operation, may damage the main

transmission input shaft.

(a). Install four bolts with washers

D Do not use clutch coupling shims under

through oil cooler mounting bracket

transmission input coupling. Inside diam

into fan bracket.

eter of clutch coupling shim is different

(b). Before tightening bolts, displace

than shim used on transmission input

cooler toward the transmission flange

coupling. Incorrect diameters can cause

to eliminate slack in that direction.

an improperly seated shim, misalignment

(c). Torque bolts to 70 - 90 inch-pounds

and cocked coupling.

(7.91 - 10.17 Nm) and safety with

(7). Torque bolts to 70 - 90 inch-pounds

lockwire (CM702).

(7.91 - 10.17 Nm).

(d). After bolts are torqued, seal around

(8). Coat threads of coupling bolt with

bolt heads with sealant (CM425).

anti-seize compound (CM112).

(9). Lubricate input shaft splines and

When installing pulley and

CAUTION

coupling splines with grease (CM111).

guard, make sure the spring pin

(10). Install input coupling shim and

in pulley is fully engaged inside hole in

coupling on transmission input shaft

pulley guard. If the spring pin does not align

with coupling bolt.

correctly with hole in pully guard, the

(11). Adjust belt tension (Ref. Cooling Blower

torque will be incorrect.

Belt Tension Check and Adjustment).

NOTE: Check coupling bolt for a minimum of

(2). Install pulley guard on main transmis

25 inch-pounds (2.82 Nm) drag torque.

sion input shaft.

(12). Torque coupling bolt to 315 - 365

(3). With belt looped around transmission

inch-pounds (35.59 - 41.24 Nm) plus

input shaft, position mounting bracket

drag torque.

on main transmission pad and loosely

(13).

369D, E, F, and 500N - Make sure belt

install two bolts with washers from the

tracks correctly (Ref. Cooling Blower

bottom of bracket and two bolts with

Belt Tracking).

washers from top of bracket.

(14). Connect drain tube to cooling blower

(4). Before tightening bolts, insert two

scroll fitting. Clamp tube to fitting with

shims between bracket and transmis

two turns of lockwire (CM702).

sion pad.

(15). Roll exhaust duct rubber connectors

(5). Verify that blower scroll clears anti-

onto scroll outlets (transmission oil

torque drive shaft by a minimum of

cooler duct and engine oil cooler duct)

0.190 inch (4.826 mm).

and secure with tie straps.

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CSP-HMI-2

MAINTENANCE MANUAL

E. 369D, E, F, and 500N − Cooling Blower

(3). Rotate the lower driver pulley by hand

Belt Tracking

in a counter-clockwise direction. Make

sure the belt tracks axially towards the

(Ref. Figure 407)

blower on the upper driven pulley.

(1). Make sure the oil cooler belt tracks

correctly.

(4). If the oil cooler belt does not track

(2). Rotate the lower driver pulley with

correctly, replace with a serviceable

your hand in a clockwise direction (as

belt.

you look at the main rotor transmission

input). Make sure the belt tracks

axially away from the blower on the

upper driven pulley.

BLOWER

DRIVEN PULLEY

NOTE 1

DRIVEN PULLEY

NOTE 2

DRIVER PULLEY

(NOTES 1,2)

NOTES;

MAIN TRANSMISSION

DRIVE SHAFT

1. TURN DRIVER PULLEY CLOCKWISE.

VERIFY BELT TRACKS AWAY FROM BLOWER.

2. TURN DRIVER PULLEY COUNTER-CLOCKWISE.

VERIFY BELT TRACKS TOWARDS BLOWER.

63-2034

Figure 407. Cooling Blower Belt Tracking

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

MAIN TRANSMISSION LUBRICATION

AND COOLING SYSTEM

INSPECTION/CHECK

1. Lubrication System Inspection

(4). Examine scroll for cracks or breaks,

and for secure attachment to hub.

(Ref. Figure 601)

(5). Examine rubber connectors at engine

(1). Inspect plumbing and system compo

oil cooler duct and transmission oil

nents from oil cooler to lubrication

cooler duct where they attach to scroll.

pump for leaks, secure attachment and

Examine ducts for damage.

damage.

(6). Look through hub support legs and, to

(2). Inspect oil cooler, lubrication pump, oil

extent possible, inspect impeller for

filter, oil pressure switch, liquid level

damage. A crack, loose rivet or dis

plug, and chip detectors for leaks,

torted vane is cause for impeller

secure attachment and damage.

replacement. Inspect mount screws and

bolts for evidence of broken slippage

(3). Inspect electrical connections at oil

mark paint.

temperature switch, oil pressure

switch, and chip detectors for absence

(7). Examine scroll drain tube for damage,

of corrosion, secure attachment and

secure attachment and clear passage.

damage.

(8). Examine mounting bracket and fan

mounting bracket for secure attach

2. Cooling Blower Inspection

ment. Check for broken lockwire at bolt

heads securing mounting bracket

(Ref. Figure 405)

cooling blower assembly.

(1). Remove blower access door and inspect

belt for damage or excessive wear. Belt

3. Cooling Blower Inspection

should be fully seated in pulley grooves.

(Disassembled)

Limited cracking or separation of belt.

Consumable Materials

(a). Belt should be fully seated in pulley

(Ref. Section 91−00−00)

grooves.

Item

Nomenclature

(b). Limited cracking or separation of belt

CM206

Chemical coating

between pulley grooves is acceptable.

CM318

Primer

Visually monitor any propagation.

CM801

Abrasive paper, silicon carbide

Belt should be replaced if any one

separation exceeds three inches in

length or if total separation exceeds

(1). Examine belt for damage or excessive

50 percent of peripheral length of

wear (Ref. Figure 405).

belt. (For belt replacement schedule,

refer to Section 05-10-00).

(2). Examine driver pulley, spring pin,

pulley guard and driven pulley for

(2). Check belt tension.

damage or excessive wear.

(3). Hand-rotate main rotor to examine all

(3). Check driven pulley retaining nut for a

visible areas of driven pulley and driver

minimum of 160 inch-pounds (18.08

pulley for damage or excessive wear.

Nm) plus drag torque. If loss of

Listen for sounds of defective bearings

torque is indicated, remove pulley nut

or of impeller touching scroll while

and inspect washer for evidence of

rotor is turned.

elongation and wear.

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

OIL PRESSURE

SENDER

LUBRICATION PUMP

MAIN TRANSMISSION

AND OIL FILTER

OIL TEMPERATURE

SENDER

GROUND WIRE

OIL COOLER

BYPASS VALVE

CHIP DETECTORS

OIL COOLER BLOWER

TRANSMISSION OIL

COOLER DUCTS

OIL COOLER

OIL LEVEL PLUG

VIEWED FROM RH SIDE OF

MAIN TRANSMISSION

NOTE 1

NOTE:

DRAIN CAP

DRAIN CAP INSTALLED AT THIS LOCATION

(EARLY CONFIGURATION ONLY)

G63-2007A

Figure 601. Main Transmission Cooling Blower and Duct

(4). Check pulley shaft and splines for

(7). Examine scroll (Ref. Figure 801) for

condition. Replace damaged flat washer

cracks, breaks and distortion.

or ring washer with flat washer. Install

Handle impeller carefully to

and torque nut to 160 - 190 inch-

CAUTION

prevent damage that could

pounds (18.08 - 21.47 Nm) plus drag

cause imbalance and require replacement of

torque.

impeller.

(5). Examine mounting bracket and fan

(8). Visually (minimum 10X magnification)

mounting bracket for cracks and

examine impeller (Ref. Figure 801) for

breaks.

cracks, deformation and separation.

(6). Examine web of mounting bracket for

(a). Look for foreign material attached to

wear.

impeller. None is permitted.

(a). Remove nicks, scratches or grooves

(b). Check for loose rivets at hub.

leaving sharp impressions in web.

Minimum acceptable web thickness:

(c). Use electroprobe or gage of equiva

0.125 inch (3.175 mm).

lent accuracy to measure depth of

scratches or nicks.

(b). Replace mounting bracket if web does

not meet 0.125 inch (3.175 mm)

(d). Use penetrating dye to examine

minimum after repair.

suspected cracks.

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CSP-HMI-2

MAINTENANCE MANUAL

(e). Scratches and nicks not exceeding

Kg). This load is to be applied at a right

0.006 inch (0.152 mm) depth are

angle to the outside face of the belt.

repairable by sanding with grade 320

Measure belt deflection without turning

abrasive paper (CM801) to blend

driven pulley, then turn driven pulley

defect into surrounding area.

1/2 turn and repeat belt deflection

measurement. Turn driven pulley an

1). Treat blended areas with chemical

additional 1/4 turn and measure belt

coating (CM206) and touch-up

deflection again.

with primer (CM318).

(a). If the tension is too high, greater

2). All other defects require replace

than 2.00 pounds (0.9072 Kg),

ment of impeller.

tension can be reduced by peeling off

a layer of the laminated shim, one at

(9). Examine shaft for damage or excessive

a time equally from both shims, until

wear. Discard seal (Ref. Figure 801).

tension falls into proper range.

Cooling Blower Belt Tension Check and

(b). If the tension is too low: Add layers

Adjustment

from a spare shim in the same

manner as removed in step (2).(a).

(1). Check that laminated shims are in

above, until tension falls into proper

position between mounting bracket and

range.

transmission fan mount assembly.

Tighten the four mounting bolts. Rotate

(3). Make a final check of bolt torque:

pulley by hand a few turns to even out

belt tension.

For 369D25100 transmission installa

tion, 65 - 75 inch-pounds (7.34 - 8.47

(2). Measure belt deflection three times at

Nm), and then lockwire drilled heads.

approximate center of one of the spans.

The force required to deflect the belt

For 369F5100 transmission installa

0.170-0.200 inch (4.32-5.08 mm) must

tion, 70 - 90 inch-pounds (7.91 -

be 1.75-2.00 pounds (0.7938-0.9072

10.17 Nm).

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

MAIN TRANSMISSION LUBRICATION

AND COOLING SYSTEM

REPAIRS

369D25630 Cooling Blower Disassembly

holding device meeting requirements of

caution above, and remove impeller

(Ref. Figure 801)

retaining nut and washer.

NOTE: Disassemble cooling blower only to ex

Be careful to prevent impeller

CAUTION

tent necessary to perform inspection, re

damage. Slight impeller defor

placement or repair of specific items. Re

mation or damage can cause imbalance.

place cooling blower bearings and belt per

Protect shaft threads and use nonmetallic

replacement schedule (Ref. Sec. 05-10-00).

mallet when performing step (8). below.

Bolts used to secure mount bracket to cool

ing blower must be self-locking type only.

(8).

Manually support impeller and sepa

rate impeller from shaft by carefully

Discard bolts if safety wired and replace

tapping end of shaft. Remove impeller,

with self-locking bolts (Ref. Figure 405).

scroll, key, spacer and any shimming

(1). Remove mounting bracket (Ref. Sec.

present.

63-20-00).

(9).

Remove bolt, retaining ring and spring

(2). Remove scroll cover.

washer from hub.

(3). Hold impeller retaining nut with socket

(10).

Use non-metallic mallet on splined end

wrench and remove driven-pulley

of shaft to drive impeller-end bearing,

retaining nut and washer.

seal, and portion of the shaft from hub.

Do not attempt to remove sleeves from

(4). Remove driven pulley. Do not forcefully

hub. Sleeves are line-reamed. If either

tap or pry; if necessary, use pulling

sleeve is defective, hub must be re

device.

placed. Remove inner retaining ring

from hub. Remove and discard O-ring

(5). Remove spacer from impeller shaft.

in upper sleeve if installed.

(6). Remove four screws and washers that

(11).

If necessary, use pulling device to

attach scroll to hub.

extract bearing and seal from shaft.

In following step, do not use

(12).

If remaining bearing cannot be driven

CAUTION

tools or other devices to hold im

from hub by tapping outer race from

peller. Tool damage can affect impeller bal

inside with nonferrous tube and mallet,

ance. Holding device must not damage shaft

re-insert shaft into bearing, drive

splines and must hold shaft with 250 - 300

bearing out and remove it from shaft as

inch-pounds (28.25 - 33.90 Nm) of torque

described in steps (10). and (11). above.

applied to impeller retaining nut.

(13).

Discard bearings. They are not to be

(7). Secure splined end of impeller shaft in

re-used.

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

SHAFT

SLEEVE

BEARING

(NOTE 1)

HUB

O-RING

SHAFT

BEARING

SLEEVE

(NOTE 2)

HUB

INNER RETAINER

RING

CAVITY FILLED

MINIMUM CLEARANCE

WITH GREASE

SCREWS AND WASHERS

TO PREVENT RUBBING

(4 PLCS)

(NOTE 3)

BOLT

SEAL (PART

BEARING

OF BEARING)

BLOWER

SCROLL

SLEEVE

SEAL

IMPELLER

SCREW AND WASHER (8

PLCS)

SPRING WASHER

WASHER KEY

NUT

SEALANT

COVER

OUTER RETAINING RING

LAMINATED

(NOTE 1)

SHIM

DRAIN TUBE

OUTLET

COVER

(NOTE 2)

NOTES:

CURRENT CONFIGURATION.

EARLY CONFIGURATION.

G63-2009-1

CLEARANCE SHALL BE 0 020-0 040 IN (0 508-1 016 MM) MINIMUM

Figure 801. 369D25630 Cooling Blower − Cross−Section View

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CSP-HMI-2

MAINTENANCE MANUAL

369D25630 Cooling Blower Reassembly

(7). Lightly grease (CM116) larger bearing

journal of shaft and bore of remaining

(Ref. Figure 801)

bearing.

On current configuration Cool

Consumable Materials

CAUTION

ing blowers, apply locking com

(Ref. Section 91−00−00)

pound (CM431) to outer race of lower bear

Item

Nomenclature

ing (impeller end) only. Do not apply locking

CM116

Grease, aircraft and instrument

compound to upper bearing (pulley end).

CM219

Methyl-ethyl-ketone

(8). Apply primer (CM321) and locking

CM220

Naphtha aliphatic

compound (CM431) to faying surfaces of

CM222

1,1,1-Trichloroethane

outer bearing race and sleeve according

CM321

Surface primer locking compound

to container instructions. Be careful to

CM425

Sealing compound

prevent compounds from entering

bearing.

CM431

Sealing, locking and retaining compound

NOTE: On newer style bearings, the metal

shield is replaced by a blue shield.

NOTE: Following procedure covers assembly of

completely disassembled cooling blower, to

(9). Insert bearing so that shield side (metal

gether with those items (belt, brackets, etc)

shield or blue disc) faces interior of hub

that form a complete unit. Use only applica

and seal side (rubber disc) faces

ble steps of procedure when disassembly is

impeller end of shaft.

less than complete. New bearings and new

seal are required; those removed are not to

(10). Arbor-press bearing simultaneously

be reused.

onto shaft journal and into sleeve.

Exert pressure equally on both races of

(1). Install inner retaining ring in hub and

bearing. At same time, exert equal

if removed at disassembly install new

pressure on splined end of shaft and

O-ring in upper bearing sleeve.

pulley end of hub casting. Bearing is to

firmly contact shaft shoulder and inner

(2). Lightly grease (CM116) smaller bearing

retaining ring.

journal of shaft, and bore of correspond

ing bearing.

MEK solvent is flammable.

WARNING

Use only in well-ventilated

NOTE: This bearing does not have a metal

area and away from heat and flame.

shield.

(11). Wipe away excess locking compound.

(3). Place bearing on shaft so that rubber

Use methyl ethyl keytone (CM219) if

seal of bearing faces splined end of

hardening begins. Leave assembled

shaft.

parts undisturbed to permit locking

compound to cure for two hours at

(4). Using tube that contacts only edge of

75°-100°F (24°-38°C), or for ten

inner race of bearing, arbor-press

minutes at 220° ±l0°F (105° ±5°C).

bearing onto journal until inner race

contacts shaft shoulder.

(12). Temporarily install lubrication fitting.

(5). Clean outer race of both bearings and

(13). Install new seal, spring washer and

faying surfaces of both hub sleeves with

outer retaining ring.

trichloroethane (CM222) and clean

(14). Fill hub cavity with grease (CM116)

cloth or paper towel.

through lubrication fitting until grease

(6). Arbor-press bearing (with shaft

seeps out around seal of bearing

installed) into sleeve. Exert pressure

nearest splined end of shaft. After

only on bearing outer race and on

lubrication, remove lubrication fitting

impeller-end of hub casting (no

and install screw and washer. Lockwire

pressure on impeller-end sleeve).

screwhead.

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MD Helicopters, Inc.

MAINTENANCE MANUAL

(15). Install hub on scroll with four screws

tightening bolts, fully displace bracket

and washers. Torque screws to 12 - 15

in direction that causes it to be closest

inch-pounds (1.36 - 1.69 Nm).

to main transmission drive shaft when

cooling blower is installed, then torque

(16). Install spacer and impeller on shaft.

bolts to 65 - 75 inch-pounds (7.34 -

8.47 Nm). Apply slippage mark paint.

(17). Install washer and locknut on end of

shaft. Using holding device on splined

(23).

(Ref. Figure 405) Install spacer, washer,

end of shaft, tighten locknut sufficiently

pulley, washer and nut on shaft. Hold

to remove all end clearance from

nut on impeller end of shaft with socket

stack-up of parts.

wrench and tighten pulley nut to 160 -

190 inch-pounds (18.08 - 21.47 Nm)

(18). Using feeler gage through an air outlet

plus drag torque.

port, measure minimum clearance

between impeller and scroll lip.

(24).

(Ref. Figure 405) Install belt on pulley

and secure mounting bracket to fan

NOTE: If minimum clearance is 0.020-0.040

mounting bracket with four bolts and

inch (0.508-1.016 mm), steps (19). and (20).

washers. Before tightening bolts, fully

below may be bypassed.

displace bracket in direction that

causes it to be closest to main transmis

(19).

If clearance is more than 0.040 inch

sion drive shaft when cooling blower is

(1.016 mm), remove impeller and

installed, then torque bolts to 65 - 75

spacer. Replace spacer with 369H5654

inch-pounds (7.34 - 8.47 Nm) and

shims as required between impeller and

lockwire drilled heads.

seal to obtain 0.020-0.040 inch

(0.508-1.016 mm) clearance. Reinstall

(25).

Clean faying surfaces of scroll and

impeller, washer and locknut. Tighten

cover with naphtha (CM220); apply

to remove all end clearance, and then

sealant (CM425) according to container

rotate impeller and check for rubbing. If

instructions before securing cover to

rubbing occurs, perform step (20).,

scroll with eight screws and washers.

otherwise proceed to step (21)..

600N5630 Cooling Blower Disassembly

(20).

If clearance is less than 0.020 inch

(Ref. Figure 802)

(0.508 mm), or if rubbing occurs when

performing previous step, disassemble

NOTE: Disassemble cooling blower only to ex

and install shim(s) between seal and

tent necessary to perform inspection, re

spacer to ensure 0.020-0.040 inch

placement or repair of specific items. Re

(0.508-1.016 mm) minimum clearance

place cooling blower bearings and belt per

and prevent rubbing.

replacement schedule (Ref. Sec. 05-10-00).

(1). Remove mounting bracket (Ref. Sec.

(21).

When clearance is properly adjusted,

63-20-25).

remove impeller, install key, impeller,

washer and locknut. Torque locknut to

(2). Hold impeller retaining nut with socket

250 - 300 inch-pounds (28.25 - 33.90

wrench and remove driven-pulley

Nm). Use care to avoid placing stress

retaining nut and washer.

on impeller or scroll. Hold splined end

of shaft in suitable device.

(3). Remove driven pulley. Do not forcefully

tap or pry; if necessary, use pulling

NOTE: Install two self-locking bolts in place of

device.

safety-wired bolts if not previously in

(4). Remove spacer from impeller shaft.

stalled.

(5). Remove two screws and washers that

(22).

(Ref. Figure 405) Secure fan mounting

attach scroll to shroud.

bracket on hub with four bolts and

washers on early configurations, or two

(6). Remove four screws six washers, and

self-locking bolts, two screws and four

two nuts that attach hub to shroud and

washers on current versions. Before

scroll. Retain shim if installed.

Page 804

Revision 36

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

SCREW

WASHER

SHROUD

NUT

WASHER

SHAFT

BEARING

HUB

SCREW

WASHER

LOCKWIRE

O-RING

SCROLL

RETAINING RING

SHIM

(NOTE 3)

BEARING

SPRING

SEAL

WASHER

(NOTE 2)

NOTE 3

IMPELLER

RETAINING RING

SHIM

NUT WASHER

(NOTE 1)

WOODRUFF KEY

NOTE:

SHIM IMPELLER TO PROVIDE 0.020-0.030 IN. (0.508-0.762 MM) AVERAGE BLADE

TRAILING EDGE TIP CLEARANCE-TO-SHROUD, MEASURED PERPENDICULARLY TO

THE SHROUD FACE. THE BLADE TRAILING EDGE IS AT THE LARGEST BLADE

DIAMETER. SHIM PRIOR TO INSTALLING SCROLL.

INSTALL SEAL WITH SMALL DIAMETER GAP IN RINGS FACING OUTSIDE OF HUB.

SHIM HUB TO PROVIDE 0.020 IN. (0.508 MM) MINIMUM GAP BETWEEN SCROLL

G63-2009-2A

AND IMPELLER

Figure 802. 600N5630 Cooling Blower − Cross−Section View

Page 805

63-21-00

Revision 36

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

In following step, do not use

600N5630 Cooling Blower Reassembly

CAUTION

tools or other devices to hold im

(Ref. Figure 802)

peller. Tool damage can affect impeller bal

ance. Holding device must not damage shaft

splines and must hold shaft with 250 - 300

Consumable Materials

inch-pounds (28.25 - 33.90 Nm) of torque

(Ref. Section 91−00−00)

applied to impeller retaining nut.

Item

Nomenclature

CM116

Grease, aircraft and instrument

(7). Secure splined end of impeller shaft in

CM219

Methyl-ethyl-ketone

holding device meeting requirements of

CM220

Naphtha aliphatic

caution above, and remove impeller

CM222

1,1,1-Trichloroethane

retaining nut and washer.

CM321

Surface primer locking compound

CM425

Sealing compound

Be careful to prevent impeller

CAUTION

CM431

Sealing, locking and retaining compound

damage. Slight impeller defor

mation or damage can cause imbalance.

Protect shaft threads and use nonmetallic

NOTE: Following procedure covers assembly of

mallet when performing step (8). below.

completely disassembled cooling blower, to

gether with those items (belt, brackets, etc)

that form a complete unit. Use only applica

(8).

Manually support impeller and sepa

ble steps of procedure when disassembly is

rate impeller from shaft by carefully

less than complete. New bearings and new

tapping end of shaft. Remove impeller,

seal are required; those removed are not to

scroll, key, spacer and any shimming

be reused.

present.

(1). Install inner retaining ring in hub and

(9).

Remove bolt, retaining ring and spring

if removed at disassembly install new

washer from hub and shroud.

O-ring in upper bearing sleeve.

(2). Lightly grease (CM116) smaller bearing

(10).

Use non-metallic mallet on splined end

journal of shaft, and bore of correspond

of shaft to drive impeller-end bearing,

ing bearing.

seal, and portion of the shaft from hub.

NOTE: This bearing does not have a metal

Do not attempt to remove sleeves from

shield.

hub. Sleeves are line-reamed. If either

sleeve is defective, hub must be re

(3). Place bearing on shaft so that rubber

placed. Remove inner retaining ring

seal of bearing faces splined end of

from hub. Remove and discard O-ring

shaft.

in upper sleeve if installed.

(4). Using tube that contacts only edge of

inner race of bearing, arbor-press

(11).

If necessary, use pulling device to

bearing onto journal until inner race

extract bearing and seal from shaft.

contacts shaft shoulder.

(12).

If remaining bearing cannot be driven

(5). Clean outer race of both bearings and

from hub by tapping outer race from

faying surfaces of both hub sleeves with

inside with nonferrous tube and mallet,

trichloroethane (CM222) and clean

re-insert shaft into bearing, drive

cloth or paper towel.

bearing out and remove it from shaft as

(6). Arbor-press bearing (with shaft

described in steps (10). and (11). above.

installed) into sleeve. Exert pressure

only on bearing outer race and on

(13).

Discard bearings. They are not to be

impeller-end of hub casting (no

re-used.

pressure on impeller-end sleeve).

Page 806

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(7). Lightly grease (CM116) larger bearing

(15). Install shim on scroll.

journal of shaft and bore of remaining

(16). Install hub and shroud on scroll with

bearing.

six screws, eight washers and two nuts.

Torque screws to 12 - 15 inch-pounds

Apply locking compound

CAUTION

(1.36 - 1.69 Nm).

(CM431) to outer race of lower

bearing (impeller end) only. Do not apply

(17). Using feeler gage through an air outlet

locking compound to upper bearing (pulley

port, measure for 0.020 inch (0.508 mm)

end).

minimum gap between impeller and

scroll.

(8). Apply primer (CM321) and locking

compound (CM431) to faying surfaces of

(18). Check for proper thread protrusion of

outer bearing race and sleeve according

six screws through nutplates and nuts

to container instructions. Be careful to

on inside of scroll.

prevent compounds from entering

(19). Install spacer and impeller on shaft.

bearing.

(20). Install washer and locknut on end of

(9). Insert bearing so that shield side (metal

shaft. Using holding device on splined

disc) faces interior of hub and seal side

end of shaft, tighten locknut sufficiently

(rubber disc) faces impeller end of shaft.

to remove all end clearance from

(10). Arbor-press bearing simultaneously

stack-up of parts.

onto shaft journal and into sleeve.

(21). Using feeler gage through an air outlet

Exert pressure equally on both races of

port, measure minimum clearance

bearing. At same time, exert equal

between impeller and scroll lip.

pressure on splined end of shaft and

pulley end of hub casting. Bearing is to

NOTE: If minimum clearance is 0.020-0.030

firmly contact shaft shoulder and inner

inch (0.508-0.762 mm), steps (19). and (20).

retaining ring.

below may be bypassed.

MEK solvent is flammable.

(22).

If clearance is more than 0.030 inch

WARNING

Use only in well-ventilated

(0.762 mm), remove impeller and

area and away from heat and flame.

spacer. Replace spacer with 369H5654

shims as required between impeller and

(11). Wipe away excess locking compound.

seal to obtain 0.020-0.030 inch

Use methyl ethyl keytone (CM219) if

(0.508-0.762 mm) clearance. Reinstall

hardening begins. Leave assembled

impeller, washer and locknut. Tighten

parts undisturbed to permit locking

to remove all end clearance, and then

compound to cure for two hours at

rotate impeller and check for rubbing. If

75°-100°F (24°-38°C), or for ten

rubbing occurs, perform step (20).,

minutes at 220° ±l0°F (105° ±5°C).

otherwise proceed to step (21)..

(23).

If clearance is less than 0.020 inch

(12). Temporarily install lubrication fitting.

(0.508 mm), or if rubbing occurs when

NOTE: Install seal with small diameter gap in

performing previous step, disassemble

rings facing outside of hub.

and install shim(s) between seal and

spacer to ensure 0.020-0.030 inch

(13). Install new seal, spring washer and

(0.508-0.762 mm) minimum clearance

outer retaining ring.

and prevent rubbing.

(14). Fill hub cavity with grease (CM116)

(24).

When clearance is properly adjusted,

through lubrication fitting until grease

remove impeller, install key, impeller,

seeps out around seal of bearing

washer and locknut. Torque locknut to

nearest splined end of shaft. After

250 - 300 inch-pounds (28.25 - 33.90

lubrication, remove lubrication fitting

Nm). Use care to avoid placing stress

and install screw and washer. Lockwire

on impeller or scroll. Hold splined end

screwhead.

of shaft in suitable device.

Page 807

63-21-00

Revision 37

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

(25).

(Ref. Figure 406) Secure fan mounting

6. Transmission and Cooling Blower Drain

bracket on hub with two self-locking

Tube Repair and Replacement

bolts, two screws and four washers.

Before tightening bolts, fully displace

Consumable Materials

bracket in direction that causes it to be

(Ref. Section 91−00−00)

closest to main transmission drive shaft

Item

Nomenclature

when cooling blower is installed, then

CM702

Lockwire CRES

torque bolts to 50 - 70 inch-pounds

CM717

Tape, pressure sensitive

(5.65 - 7.91 Nm) and screws to 65 - 75

inch-pounds (7.34 - 8.47 Nm). Apply

slippage mark paint.

(1). Disconnect drain tubes from transmis

sion cooling blower, and from drain

fittings and weld assemblies at firewall.

(26).

(Ref. Figure 406) Install spacer, washer,

Release supporting nylon straps and

pulley, washer and nut on shaft. Hold

remove drain tubes (Ref. Figure 601).

nut on impeller end of shaft with socket

wrench and tighten pulley nut to 160 -

(2). Inspect drain tubes, drain fittings, weld

190 inch-pounds (18.08 - 21.47 Nm)

assemblies and connectors for damage

plus drag torque.

and clear passage.

(3). Repair damaged flexible drain tubes

with tape (CM716).

(27).

(Ref. Figure 406) Install belt on pulley

and secure mounting bracket to fan

(4). Install drain tubes as follows:

mounting bracket with four bolts and

(a). Attach upper ends of drain tubes to

washers. Before tightening bolts, fully

transmission and cooling blower.

displace bracket in direction that

Secure with double wraps of lockwire

causes it to be closest to main transmis

(CM702).

sion drive shaft when cooling blower is

installed, then torque bolts to 65 - 75

(b). Route drain tubes and secure with

inch-pounds (7.34 - 8.47 Nm) and

nylon straps. Position tubes so that

lockwire drilled heads.

no drainage traps are formed.

(c). Secure lower ends of drain tubes to

fittings and weld assemblies with

(28).

Clean faying surfaces of scroll and

double wraps lockwire (CM702).

cover with naphtha (CM220); apply

sealant (CM425) according to container

(d). Insert lower end of metal drain tube

instructions before securing cover to

through grommet in skin and slip

scroll with eight screws and washers.

upper end of tube into weld assembly.

Wrap tube with one layer of 1 inch

(2.54 cm) wide tape (CM717) at

clamp-attach point, and install

5. Cooling Blower Cleaning (Disassembled)

clamp.

7. Installation of Heating System and Oil

Consumable Materials

Cooling Line Standoff Clamps (0003D −

(Ref. Section 91−00−00)

0539D)

Item

Nomenclature

(Ref. Figure 803) The following information

list a procedure for installing standoff clamps

CM234

Solvent, dry-cleaning

on the 369D292490 heating system hose and

on the 369D25710 main rotor transmission oil

cooling line to eliminate chafing between the

(1). Clean all usable metal parts with

oil cooling lines and chafing of the oil cooling

solvent spray (CM234). Remove

lines by the heating system hose. A protective

remnants of locking compound with

bushing is also installed to prevent chafing

loctite remover (CM216).

between the oil cooling lines.

Page 808

Revision 36

63-21-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(1). Remove aft compartment interior trim

(4). Check installation of standoff clamps to

panels and left Sta. 124.00 bulkhead

ensure adequate clearance between

access door to gain access to work area.

369D25709 and 369D25710 oil cooling

lines and between oil cooling lines and

NOTE: Inspect the 369D292490 heating sys

369D292490 heating system hose.

tem hose and 369D25709 and 369D25710

main transmission oil cooling lines for evi

NOTE:

dence of chafing, kinking or damage at area

of L/H aft section channel assembly.

D Later Model 369D helicopters have

369D26544-3 closure plate (with grom

(2). If not already installed, install

met) installed on L/H aft section channel.

NAS1713D30N clamp on heating

Remove plate from channel, if presently

system hose and NAS1713D8N clamp

installed, to preclude interference with oil

on 369D25710 oil cooling line. Connect

cooling lines.

clamps with screw, washer and nut.

D Later model 500D helicopters have

(3). If not already installed, install new

HS4194-6 standoff bracket installed on

C-SB-16-8 bushing snug against nut

channel with MS21919DG30 clamp to se

on 369D25709 oil cooling tube assembly

cure heating hose. Install standoff brack

(View A-A). Reposition clamp assembly

et and clamp, if not presently installed on

securing 369D25709 (lower) and

helicopter.

369D25710 (upper) oil cooling tube

assemblies to accommodate installation

(5). Reinstall bulkhead access door and

of bushing.

interior trim panels.

Page 809

63-21-00

Revision 36

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

CLAMP ASSY

369D25710 OIL COOLING

(RELOCATED)

TUBE ASSY

369D26544-3 CLOSURE PLATE

(REMOVE IF PRESENTLY INSTALLED

ON AFT SECTION CHANNEL)

(ROTATED)

369D25709 OIL COOLING

TUBE ASSY

VIEW A - A

C-5B-16-8 BUSHING

(NOTE 3)

369D25710 OIL COOLING

HS4194-6 STANDOFF (NOTE 1)

TUBE ASSY (REF)

MS20470AD3 RIVET (2)

C-5B-16-8 BUSHING

369D23024 AFT SECTION

CHANNEL ASSY

369D25709 OIL COOLING

(CANT. STA. 124.00)

TUBE ASSY

NAS1713D8N CLAMP (NOTE 2)

NAS1096-7 SCREW

MS21919DG30 CLAMP (NOTE 1)

AN960PD10L WASHER (2)

NAS1096-3-7 SCREW

MS21043-3 NUT

AN960PD10L WASHER

369D25709 OIL COOLING

TUBE ASSY

NAS1713D8N CLAMP (EXISTING)

AN743-12 BRACKET

369D292490 HEATING HOSE

NAS1096-3-7 SCREW (2)

MS21043-3 NUT (3)

AN960PD10L WASHER (4)

NAS1713D30N CLAMP

(NOTE 2)

NAS1713D30N CLAMP

(EXISTING)

NOTES:

PRESENTLY INSTALLED ON LATE-MODEL HELICOPTERS.

LOCATE NEW CLAMPS APPROXIMATELY AS SHOWN ON

COOLING TUBE AND HEATING HOSE ASSEMBLIES.

AFTER INSTALLATION OF BUSHING, ROTATE BUSHING SO

G63-2026A

THAT SPLIT IN BUSHING IS FACING DOWN

Figure 803. Installation of Standoff Clamps − Heating and Oil Cooling Lines

Page 810

Revision 22

63-21-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

ROTOR BRAKE

MAINTENANCE PRACTICES

When working with hydrau

pressure is produced; this pressure is trans

WARNING

lic systems, special care

mitted through the tubing to the caliper

must be taken to prevent entrance of

assembly where it acts on the pistons. This

dust, moisture or other foreign materi

causes the pucks to apply clamping pressure

al. System contamination can cause

(braking force) to the brake disc. System

malfunctions which could cause injury

pressure is held within safe limits, regardless

to personnel or equipment damage.

of the force applied to the brake handle, by

operation of the pressure-relief valve. When

1. Rotor Brake

hydraulic pressure exceeds 500 psig (3447

kPa), the pressure-relief valve opens, venting

The rotor brake enables the pilot to manually

excess pressure back to the master cylinder.

brake the rotor system to a stop by operating a

When application of force is discontinued,

single brake handle. The handle is installed on

caliper pistons (and the pucks) are retracted

the upper left (or upper right, depending on

by return springs in the caliper assembly.

helicopter seating configuration) side of the

Puck-to-disc clearance is maintained by

canted bulkhead 78.50 control tunnel in the

action of a self-adjusting mechanism in the

pilot's compartment. Operation of the brake

caliper assembly. The original equipment

handle actuates a master cylinder, causing

tachometer generator is replaced by a new unit

dual pucks to grip a brake disc installed on the

that is included in the rotor brake installation

tail rotor drive shaft. Braking force is trans

to provide clearance between the tachometer

mitted through the main transmission to the

generator and the brake disc. The original

main rotor. A friction clip secures the handle in

equipment electrical connector (P202),

an out-of-the-way position when the brake is

installed on the aft fuselage wiring harness

not in use.

near the main transmission, is replaced with a

new plug which mates with the receptacle on

The rotor brake installation includes:

the new tachometer generator.

(1). A master cylinder with an actuating

3. Rotor Brake Troubleshooting Procedure

handle mechanism (master cylinder

and linkage assembly).

(Ref. Table 201)

(2). A caliper assembly with dual opposing

4. Master Cylinder Servicing

pistons to which friction pads (brake

(Ref. Figure 401)

pucks) are attached.

(3). A brake disc installed on the tail rotor

Consumable Materials

drive shaft coupling at the aft end of

(Ref. Section 91−00−00)

the main transmission.

Item

Nomenclature

(4). A hydraulic pressure relief valve.

CM123

Hydraulic fluid

(5). A tachometer generator.

Rotor brake installation servicing includes

(6). Six stainless steel hydraulic tubing

adding hydraulic fluid (CM123) to the master

assemblies and associated fittings.

cylinder reservoir, and bleeding air from the

system.

(7). Attaching and mounting hardware.

(1). Remove interior trim to gain access to

(8). A trim panel assembly and installation.

master cylinder.

(2). Disconnect tube assembly from forward

2. Rotor Brake Operation

nipple and move end of tube assembly

When manual force is applied to the brake

carefully aside to permit removal of

handle (master cylinder piston), hydraulic

master cylinder cap.

Page 201

63-22-00

Revision 20

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

(3). Remove attaching screws, cap with

NOTE: Hose material should be resistant to de

assembled hydraulic parts, and gasket

terioration from exposure to hydraulic fluid.

from master cylinder. Replace gasket.

A glass container should be used to catch

bleed screw outflow so that bubbles of escap

ing air are clearly visible. The following fill

(4). Fill master cylinder reservoir with

ing and bleeding procedure is best per

clean hydraulic fluid (CM123) within

formed by two persons, one to operate the

1/8 to 1/4 inch (3.175-6.35 mm) of the

brake handle, and one to open and close the

top. Install cap with assembled hydrau

bleed screws.

lic parts, new gasket, and attaching

screws. Do not tighten screws if

(3). Connect a length of 1/4 inch (6.35 mm)

hydraulic system is to be bled.

ID hose on reducer and insert free end

of hose in a container to catch any

hydraulic fluid that may be bypassed by

(5). If hydraulic system has been opened,

the relief valve. Connect a second

e.g. as for replacement of components,

length of 1/4 inch (6.35 mm) ID hose on

perform procedural steps to bleed the

one bleed screw on caliper assembly

hydraulic system.

and submerge free end of hose in clean

hydraulic fluid (CM123) in a glass

NOTE: It is not necessary to bleed the system if

container.

only a small amount of fluid is required to

fill the reservoir, and if the system has not

(4). Remove attaching screws and master

been opened.

cylinder cap. Fill reservoir with clean

hydraulic fluid (CM123) within 1/8 -

1/4 inch (3.175-6.35 mm) of top of

(6). Tighten attaching screws to secure cap

chamber. Replace cap, do not tighten

on master cylinder. Connect tube

attaching screws.

assembly to nipple.

NOTE: Verify that master cylinder reservoir is

kept full of fluid throughout the bleeding

(7). Reinstall components removed for

process.

access to the master cylinder assembly.

(5). Open one bleed screw and operate

brake handle slowly through a full

5. Rotor Brake Hydraulic System Bleeding

down stroke to force hydraulic fluid out

of master cylinder reservoir and into all

other parts of the system. Close bleed

Consumable Materials

screw and return handle to ”up”

(Ref. Section 91−00−00)

position. Remove cap, refill master

Item

Nomenclature

cylinder reservoir, and replace cap.

CM123

Hydraulic fluid

(6). Repeat step (5). several times to ensure

that entire hydraulic system is filled

with fluid, and that no air remains in

The rotor brake hydraulic system must be bled

system.

to remove entrapped air whenever the system

NOTE: The presence of bubbles in the bleed

has been opened for any reason.

screw outlet flow indicates air is being

forced out of the system and absence of

(1). Remove interior trim for access to the

bubbles indicates all air has been bled from

master cylinder assembly and bleed

the system.

screws on caliper assembly (if applica

ble).

(7). Remove bleeder hose from first bleed

screw and connect it on second bleed

screw.

(2). Disconnect tube assembly from reducer

in relief valve and nipple in master

(8). Repeat steps (5). and (6). until bleed

cylinder cap.

screw outlet flow is clear of bubbles.

Page 202

Revision 20

63-22-00

MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(9). Remove fluid catch containers and

7. Master Cylinder Assembly Overhaul

hoses. Ensure both bleed screws are

tightly closed. Raise brake handle to

(1). Remove defective master cylinder

stowed position and engage in handle

assembly.

retainer assembly. Verify that caliper

pistons (and attached brake pucks) are

(2). Disassemble unit and replace defective

retracted when handle is raised.

parts with components of overhaul kit

(Vendor PN 12-8310), using manufac

(10). Make final check of fluid level in

turer's instructions supplied with kit.

master cylinder reservoir and replen

ish, if necessary. Secure gasket and cap

(3). Install overhauled master cylinder

with attaching screws.

assembly.

(11). Connect tube assembly to nipple in cap

and to reducer in relief valve and

8. Caliper Assembly Overhaul

tighten tube nuts.

(1). Remove defective caliper assembly.

6. Rotor Brake Component Repair

The master cylinder assembly or caliper

(2). Disassemble unit and replace defective

assembly may be overhauled as necessary.

parts with components of overhaul kit

Overhaul kits are available from MD Helicop

(Vendor PN 12-11780), using manufac

ters Inc. or an approved MD Helicopter service

turer's instructions supplied with kit.

center. Other parts must be replaced when

damaged or otherwise unserviceable.

(3). Install overhauled caliper assembly.

Page 203

63-22-00

Revision 42

CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

Table 201. Troubleshooting Rotor Brake Installation

Symptom

Isolating Step

Corrective Action

Brake actuating handle creeps

Defective master cylinder assembly.

Remove defective master cylinder

downward under sustained force,

assembly and replace with new unit,

with hydraulic fluid leakage from

or overhaul and reinstall old unit.

master cylinder assembly.

Brake actuating handle creeps

Defective caliper assembly.

Remove defective caliper assembly

downward under sustained force,

and replace with new unit, or

with hydraulic fluid leakage from

overhaul and reinstall old unit.

caliper assembly.

‘Spongy‘ feel at brake actuating

Air in hydraulic system.

Bleed air from hydraulic system.

handle when force is applied.

Hydraulic fluid at low level in master

Add fluid to master cylinder

cylinder reservoir.

assembly and bleed air from

hydraulic system.

Rotor brake system fails to slow

Any of above components or system

Follow applicable corrective action

rotor effectively.

faults.

procedures.

Brake pucks worn excessively.

Remove defective caliper assembly,

replace defective pucks and reinstall

repaired unit.

Brake pucks create noises, such

Glazed or worn brake pucks.

Remove defective caliper assembly,

as squeals or squeaks, when

replace defective pucks and reinstall

brakes are applied.

repaired unit.

Brake disc creates noises, such

Scored or damaged brake disc.

Remove defective brake disc and

as squeals or squeaks, when

replace with new disc.

brakes are applied.

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MAINTENANCE MANUAL

ROTOR BRAKE

REMOVAL/INSTALLATION

When working with hydrau

nience panel cover assembly from

WARNING

lic systems, special care

convenience panel assembly.

must be taken to prevent entrance of

(4). Disconnect electrical wiring and

dust, moisture or other foreign materi

communications cables from compo

al. System contamination can cause

nents on back of convenience panel

malfunctions which could cause injury

assembly. If cabin heating option is

to personnel or equipment damage.

installed on aircraft, disconnect heated

air duct from panel-mounted diffuser.

1. Rotor Brake Component Access

Remove attaching screws and conve

The following items must be removed to gain

nience panel assembly from aft side of

access for removal of rotor brake components.

canted bulkhead 78.50 structure.

Removal should be limited to damaged or

(5). Remove transmission cover panel

defective parts for repair, overhaul or replace

assembly from fuselage structure.

ment, or to remove certain items for access to

other components.

(6). Cover exposed trim panels to prevent

damage and soiling.

The master cylinder assembly, linkage

assembly and hydraulic relief valve are

(7). Remove main transmission from

installed on or attached to the helicopter

aircraft (Ref. Sec. 63-20-00/25).

structure. Removal of these components

require access from the crew compartment.

(8). Remove tail rotor (Ref. Sec. 64-20-00),

Hydraulic tube assembly is not attached to the

tail rotor transmission (Ref. Sec.

helicopter structure. Access from the passen

63-25-10) and tail rotor drive shaft

ger/cargo compartment is required for removal

(Ref. Sec. 63-15-10).

of hydraulic tube assembly.

2. Master Cylinder Assembly Replacement

The caliper assembly and related hydraulic

(Ref. Figure 401 and Figure 402)

items, caliper mounting bracket, tachometer

generator, brake disc and tail rotor drive

A. Master Cylinder Assembly Removal

coupling are installed on the main transmis

sion. Removal of these components require

The master cylinder assembly is bolted to the

that certain access provisions be made and

bracket of the master cylinder linkage assem

that the main transmission, and attached rotor

bly and is connected hydraulically to the

brake components, be removed from the

caliper assembly. Remove master cylinder

aircraft.

assembly as follows:

NOTE: Component removal can be accom

(1). Remove trim panels to gain access to

plished with the doors in place. However, op

master cylinder.

erations are facilitated with the doors re

moved.

(2). Disconnect tube assembly from nipple,

and tube assembly from elbow, taking

(1). Remove both crew compartment and

special care to catch any hydraulic fluid

cargo/passenger compartment doors.

that drains or drips from tube assem

blies or fittings when the system is

(2). Remove crew compartment seats.

opened.

(3). Remove map case assembly from

NOTE: If old master cylinder assembly is to be

forward side of canted bulkhead 78.50

reinstalled, removal of tube assembly, nip

structure. Remove both (LH and RH)

ples, and elbow may not be necessary unless

upper forward panel assemblies from

the tube assembly or fittings are damaged

bulkhead structure. Remove conve

or defective.

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MAINTENANCE MANUAL

(3). Remove tube assembly from nipple.

NOTE: Mounting holes in bracket are elon

Remove nipples from cap, and elbow

gated to enable lateral position adjustment

from master cylinder.

of master cylinder assembly.

(4). Remove nuts, washers, bolts, stop, and

(6). With actuating handle in stowed

master cylinder assembly from bracket.

position, adjust position of master

Drain residual hydraulic fluid from

cylinder assembly so that clearance

master cylinder assembly.

(measured with a thickness gage)

between actuating lever (Ref.

(5). Install protective caps or plugs on open

Figure 905) and master cylinder piston

ends of disconnected tube assemblies,

is 0.020-0.040 inch (0.508-1.016 mm).

and open ports or fittings in master

cylinder assembly to prevent entry of

(7). Install tube assembly on aft nipple.

contaminants.

Connect tube assembly to forward

nipple and connect tube assembly to

B. Master Cylinder Assembly Installation

elbow.

Consumable Materials

(8). Fill and bleed the hydraulic system.

(Ref. Section 91−00−00)

Item

Nomenclature

(9). Reinstall components removed for

access to the master cylinder assembly.

CM434

Thread sealant

3. Master Cylinder Linkage Assembly

NOTE: Steps (1). thru (3). below apply only to

Replacement

installation of a new master cylinder assem

bly.

(Ref. Figure 402)

(1). Remove attaching screws and vendor-

A. Master Cylinder Linkage Assembly

supplied cap from master cylinder.

Removal

Vendor supplied cap is not used.

The bracket assembly of the master cylinder

(2). Rework vendor-supplied gasket (Ref.

linkage assembly is permanently installed on

Figure 906).

the canted bulkhead Sta. 78.50 vertical

member by four Jo-bolt blind fasteners. Once

(3). Replace reworked gasket and new cap

installed, the Jo-bolts cannot be removed

on master cylinder and secure with

except by destructive procedures. The master

attaching screws installed finger tight.

cylinder and linkage assembly may be disas

NOTE: Cap must be installed correctly with re

sembled, leaving the bracket assembly

spect to taper of threaded holes.

attached to the structure. Disassembly should

be limited to that necessary for removal of

(4). If new master cylinder assembly is

damaged or defective parts.

being installed, or if hydraulic fittings

have been removed from a usable unit,

(1). Remove master cylinder.

coat all but first two tapered pipe

threads of nipples and elbow with

When components are as

WARNING

thread sealant (CM434). Install nipples

sembled, spring force is con

in cap and elbow in master cylinder.

stantly exerted to inhibit inadvertent

brake application. Care must be exer

(5). Place one washer and stop on bolts and

cised as the spring is disengaged to

insert bolts through master cylinder.

prevent injury to personnel or equip

Place two washers on each bolt as

ment damage.

spacers. Position assembled parts on

bracket (Ref. Figure 402) and install

(2). Manually restrain movement of lever

one washer on each bolt. Install nuts

and attached parts. Carefully disengage

finger tight to hold master cylinder

end of spring from under head of clevis

assembly and stop in position.

pin. Release spring force carefully.

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MAINTENANCE MANUAL

STOP

BRACKET

ASSY

NUT

WASHER

BOLT

ACTUATING LEVER

GRIP

SPACER

NUT

WASHER

COTTER

HANDLE

ROLL PIN

COTTER PIN

SPRING

NUT

WASHER

FITTING

WASHER

CLEVIS PIN

G63-2006

Figure 402. Master Cylinder Linkage Assembly

(3). Remove cotter pin, nut, washer, spring,

B. Master Cylinder Linkage Assembly

and lever with assembled handle parts

Installation

from pin.

Installation of the master cylinder linkage

assembly will be limited to re-assembly of

(4). Remove cotter pin, washers, and clevis

components to the bracket assembly.

pin, and separate assembled handle

parts from lever. Remove nut, spacer,

When the unit is assembled,

and bolt from lever.

WARNING

the spring is under restraint

and, if accidentally or inadvertently re

leased, could cause injury to personnel

(5). Drive two spring pins out of fitting and

or equipment damage.

handle and separate parts. Remove grip

from handle.

(1). Re-assembly procedures are essentially

the reverse of disassembly procedures,

(6). Remove nut and washer from pin, and

with special care being given to steps

remove pin from bracket assembly.

involving spring.

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MAINTENANCE MANUAL

(2). If cotter pins or spring pins have been

NOTE: If old caliper assembly is to be rein

removed, use new parts for reassembly.

stalled, it is not necessary to remove hy

draulic fittings except for replacement of de

fective or damaged parts.

4. Caliper Assembly, Brake Disc, and Drive

Coupling Replacement (369D25100

Transmission)

(4). Remove coupling bolt that is used to

secure drive coupling on transmission

(Ref. Figure 403)

output shaft so that disc/coupling unit

is free to slide on shaft splines.

A. Caliper Assembly, Brake Disc, and Drive

Coupling Removal (369D25100

(5). Note and record, for re-assembly

Transmission)

reference, placement of 18 washers

used as spacers between caliper

The caliper assembly is bolted to a mounting

assembly and mounting bracket, or

bracket which is installed on the main

under heads of attaching bolts.

transmission tail rotor cover. The brake disc is

bolted on the drive coupling which is installed

The caliper assembly consists of

on the transmission output shaft. For clarity,

CAUTION

two identical halves held togeth

the brake disc and drive coupling are consid

er by the attaching bolts. Care should be

ered as a single item (disc/coupling unit).

used to avoid dropping parts when bolts are

removed.

Although the caliper assembly and the

disc/coupling unit are not mechanically

connected, they are installed on the transmis

(6). Hold caliper assembly and unscrew

sion with the outer portion of the disc posi

attaching bolts out of mounting brack

tioned between the two halves of the caliper

et. Slide disc/coupling unit away from

assembly (Ref. Figure 404). This arrangement

transmission and remove caliper

makes it necessary to remove both units

assembly and attaching hardware.

(partially, at least) at the same time. Removal

operations require that the main transmission

(7). If caliper assembly is to be reused and

be removed from the aircraft with the rotor

some time will elapse before re-assemb

brake components installed. Proceed as

ly, remove disc/coupling unit, position

follows:

caliper assembly (and assembled parts)

on mounting bracket and screw bolts

(1). Remove main transmission and

into bracket to hold parts until time for

attached rotor brake components from

re-assembly.

aircraft (Ref. Sec. 63-20-00/25).

(8). If disc/coupling unit is to be reinstalled,

(2). Disconnect tube assembly from caliper

and some time will elapse before

mounted tees. Remove tube assembly

re-assembly, slide unit back on trans

and interconnect tee as a unit.

mission shaft and install coupling bolt

finger tight to hold parts until time for

NOTE:

re-assembly.

D It is not necessary to disconnect tube as

semblies from tee except for replacement

Axial position of the drive

of defective and damaged parts.

WARNING

coupling is critical as it con

D New bleed screws are included with the

trols the mechanical interface between

new caliper assembly.

the coupling and the tail rotor drive

shaft. Out-of-tolerance axial coupling

(3). If caliper assembly is to be replaced by

loads can contribute to coupling fail

a new unit, remove two bleed screws

ure which could result in injury to per

from adapters, remove adapters from

sonnel and equipment damage. Refer

tees, and remove tees from caliper

to Sec. 63-10-00 for coupling reinstalla

assembly.

tion.

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MAINTENANCE MANUAL

(9). If either disc or coupling is to be

Molykote metal protector

WARNING

replaced by a new part, slide disc/coup

contains perchloroethylene.

ling unit off shaft, leaving shim wash

It should be used in a well-ventilated

ers in place. Remove nuts, washers, and

area, and the precautions normally fol

bolts and separate disc and coupling. If

lowed when working with the chlori

coupling is being replaced, measure

nated solvent should be implemented.

(and record for re-assembly reference)

Solvents used to dilute this material, as

overall length of old coupling at three

well as metal-cleaning or alkali cleans

separate peripheral locations. Calculate

ers, should only be used with adequate

and record the average value.

ventilation. Follow handling precau

tions on the solvent's container label.

B. Caliper Assembly, Brake Disc and Drive

NOTE: Couplings should be treated with moly

Coupling Installation (369D25100

kote metal protector (CM202) after each

Transmission)

washing with any solvent or detergent.

(4). Spray molykote metal protector

Consumable Materials

(CM202) on the interior and exterior

(Ref. Section 91−00−00)

surfaces of Bendix coupling diaphragm

Item

Nomenclature

packs. Spray or dip flange in molykote

metal protector. Eliminate excess liquid

CM112

Anti-seize compound high temperature

by gently blowing with compressed air

CM117

Grease

(dilute to 10% perchloroethylene). Cure

for 8 hours at room temperature, or 15

CM202

Metal protector, aerosol

minutes at 150°F (65°C).

CM434

Thread sealant

(5). Coat, completely but sparingly, splines

CM702

Lockwire CRES

of transmission output shaft with

grease (CM117) and threads of coupling

bolt with anti-seize compound

(1). Position brake disc on drive coupling

(CM112), or equivalent. Start disc/coup

with raised center side of disc seated

ling unit on shaft.

firmly on shoulder of coupling, and with

bolt holes aligned. Insert four bolts

To ensure optimum brake opera

CAUTION

through disc and coupling flange,

tion and minimize equipment

install washers and nuts on bolts, and

damage, caliper-to-disc clearances on both

torque nuts (in an alternating se

sides of disc should be equal, or as nearly

quence) to 100 - 140 inch-pounds

equal as possible. Clearance adjustment is

(11.30 - 15.82 Nm).

accomplished by varying number of shim

washers, 0.032 inch (0.8128 mm) thick,

placed between the caliper assembly and its

The main transmission must

mounting bracket. Nine washers are pro

WARNING

be installed in the aircraft

vided for each attaching bolt; those not used

with special care to avoid damage to

as shims should be placed under bolt heads.

rotor brake components. Installation

Washer distribution should be the same for

damage could lead to system failure

both bolts.

which could result in injury to person

nel and equipment damage.

(6). Hold assembled parts with caliper

assembly over edge of disc, slide

disc/coupling unit on shaft, and move

(2). Install transmission in aircraft (Ref.

caliper assembly against mounting

Sec. 63-20-00/25).

bracket at the same time. Screw bolts

into bracket to hold caliper assembly

(3). Determine correct shimming for

firmly in position. Screw coupling bolt

coupling (Ref. Sec. 63-10-00).

into shaft to secure disc/coupling unit.

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MAINTENANCE MANUAL

(7). Measure brake caliper housing-to-disc

NOTE: It is not necessary to remove washers

clearances on both sides of disc with a

used as spacers except for replacement.

thickness gage. If clearances are equal

Nuts may be replaced on studs until time for

within 0.032 inch (0.8128 mm), torque

re-assembly to prevent loss of parts.

attaching bolts to 160 - 190 inch-

B. Caliper Mounting Bracket Installation

pounds (18.0821.47 Nm) and secure

(369D25100 Transmission)

with corrosion-resistant lockwire

(CM702) (Ref. Figure 405). Torque

The following procedures assume that the

coupling bolt per Section 63-10-00.

transmission has been removed from the

aircraft for removal of the mounting bracket.

NOTE: Clearance differences greater than

0.032 inch (0.8128 mm) can be reduced by

Consumable Materials

rearranging washers on caliper attaching

(Ref. Section 91−00−00)

bolts.

Item

Nomenclature

(8). To adjust clearances, hold caliper

CM702

Lockwire CRES

assembly and unscrew bolts from

mounting bracket. Transpose washers

(1). Place three washers on each of the four

on bolts as required. Reassemble parts,

mounting studs (1, 2, 10, and 11 o'clock

and recheck clearances.

positions) as spacers. Position mounting

(9). If new caliper assembly was installed or

bracket on studs, install washers and

if hydraulic fittings were removed from

nuts, and torque nuts to 50 - 75

old unit, coat all but first two threads of

inch-pounds (5.65 - 8.47 Nm).

two bleed screws, tees, and plugs with

(2). Secure installation with lockwire

thread sealant (CM434) or equivalent.

(CM702) (Ref. Figure 405).

Install plugs and tees in caliper

assembly, screw adapters on tees, and

(3). Reinstall transmission as required (Ref.

install bleed screws in adapters.

Sec. 63-20-00/25).

(10). Connect tube assemblies and tee unit to

6. Caliper Assembly, Brake Disc, and Drive

tees.

Coupling Replacement (369F5100

Transmission)

5. Caliper Mounting Bracket Replacement

(Ref. Figure 406)

(369D25100 Transmission)

A. Caliper Assembly, Brake Disc, and Drive

(Ref. Figure 403)

Coupling Removal (369F5100

Transmission)

A. Caliper Mounting Bracket Removal

(369D25100 Transmission)

The caliper assembly is bolted to the main

transmission anti-torque cover. The brake disc

The caliper mounting bracket is attached to

is bolted on the drive coupling which is

the main transmission tail rotor cover by

installed on the transmission output shaft. For

special nuts installed on four of the studs used

clarity, the brake disc and drive coupling are

for installation of the cover. The caliper

considered as a single item (disc/coupling

assembly is bolted to the mounting bracket.

unit). Although the caliper assembly and the

Bracket removal requires that the main

disc/coupling unit are not mechanically

transmission be removed from the aircraft

connected, they are installed on the transmis

with the rotor brake components installed.

sion with the outer portion of the disc posi

tioned between the two halves of the caliper

(1). Remove main transmission (and

assembly. This arrangement makes it neces

attached rotor brake components) from

sary to remove both units (partially, at least)

aircraft (Ref. Sec. 63-20-00/25).

at the same time. Removal operations require

(2). Remove attaching nuts and washers,

that the main transmission be removed from

and remove mounting bracket from

the aircraft with the rotor brake components

studs.

installed.

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MAINTENANCE MANUAL

(1). Remove main transmission (and

(8). If disc/coupling unit is to be reinstalled,

attached rotor brake components) from

and some time will elapse before

aircraft (Ref. Sec. 63-25).

re-assembly, slide unit back on trans

mission shaft and install coupling bolt

(2). Disconnect tube assembly from caliper

finger tight to hold parts until time for

mounted tees. Remove tube assembly

re-assembly.

and interconnect tee as a unit.

Axial position of the drive

NOTE: It is not necessary to disconnect tube

WARNING

coupling is critical as it con

assemblies from tee except for replacement

trols the mechanical interface between

of defective and damaged parts.

the coupling and the tail rotor drive

shaft. Out-of-tolerance axial coupling

(3). If caliper assembly is to be replaced by

loads can contribute to coupling fail

a new unit, remove two bleed screws

ure which could result in injury to per

from adapters, remove adapters from

sonnel and equipment damage. Refer

tees, and remove tees from caliper

to Sec. 63-15 for coupling reinstalla

assembly.

tion.

NOTE: If old caliper assembly is to be rein

(9). If either disc or coupling is to be

stalled, it is not necessary to remove hy

replaced by a new part, proceed as

draulic fittings except for replacement of de

follows:

fective or damaged parts.

(a). Slide disc/coupling unit off shaft,

(4). Remove coupling bolt that is used to

leaving shim washers in place.

secure drive coupling on transmission

output shaft so that disc/coupling unit

(b). Remove nuts, washers, and bolts and

is free to slide on shaft splines.

separate disc and coupling.

(5). Note and record, for re-assembly

(c). If coupling is being replaced, mea

reference, placement of 18 washers

sure (and record for re-assembly

used as spacers between caliper

reference) overall length of old

assembly and mounting bracket, or

coupling at three separate peripheral

under heads of attaching bolts.

locations.

The caliper assembly consists of

(d). Calculate and record the average

CAUTION

two identical halves held togeth

value.

er by the attaching bolts. Care should be

used to avoid dropping parts when bolts are

B. Caliper Assembly, Brake Disc and Drive

removed.

Coupling Installation (369F5100

Transmission)

(6). Hold caliper assembly and unscrew

attaching bolts. Slide disc/coupling unit

The following procedure is for installation of

away from transmission and remove

the rotor brake caliper assembly. The caliper

caliper assembly and attaching hard

assembly should be installed on the transmis

ware.

sion before the transmission is installed in the

helicopter.

(7). If caliper assembly is to be reused and

some time will elapse before re-assemb

ly, remove disc/coupling unit, position

Consumable Materials

caliper assembly (and assembled parts)

(Ref. Section 91−00−00)

on transmission and insert bolts to hold

Item

Nomenclature

parts until time for re-assembly.

CM434

Thread sealant

NOTE: New bleed screws are included with the

CM702

Lockwire CRES

new caliper assembly.

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MAINTENANCE MANUAL

NOTE:

(5). Install plugs and tees in caliper

assembly, screw adapters on tees and

D AN960-616LL washers are to be used for

install bleed screws in adapters.

adjusting caliper-to-disc clearance.

(6). Connect tube assemblies and tee units

D Nine washers are used on each attaching

to tees.

bolt; those not used as shims should be

placed under bolt heads. Washer distribu

7. Hydraulic Relief Valve Replacement

tion should be the same for both bolts.

(Ref. Figure 401)

(1). Insert two bolts with equal number of

A. Hydraulic Relief Valve Removal

washers through the caliper (washers

can be on either side of caliper as

The hydraulic relief valve is attached by

needed) and install two bushings.

means of a clamp to the canted bulkhead 78.50

vertical member, and is connected hydraulical

NOTE: On the 369F5100 transmission, the

ly between the master cylinder assembly and

brake caliper bolts directly to the transmis

the caliper assembly. Remove the relief valve

sion.

as follows:

(1). Remove crew compartment hardware

(2). Mount the caliper assembly over disc

and fittings for access to hydraulic

and thread bolts into transmission.

relief valve assembly.

To ensure optimum brake opera

(2). Disconnect tube assembly from reducer

CAUTION

tion and minimize equipment

installed in relief valve. Disconnect

damage, caliper-to-disc clearances on both

tube assembly from relief valve, taking

sides of disc should be equal, or as nearly

special care to catch any hydraulic fluid

equal as possible. Clearance adjustment is

that drains or drips from tube assem

accomplished by varying number of 0.032

blies, reducer, or relief valve when the

inch (0.8128 mm) thick shim washers placed

system is opened. Remove reducer and

between the caliper assembly and transmis

O-ring packing from relief valve.

sion.

Discard O-ring packing.

(3). Measure brake caliper housing-to-disc

NOTE: Because of limited access, it may be

clearances on both sides of disc with a

more convenient to disconnect tube assem

feeler gage. If clearances are equal

bly from tee before removing tube assembly

within 0.032 inch (0.8128 mm), torque

from relief valve. If so, remove tube assem

attaching bolts to 160 - 190 inch-

bly from tee; remove relief valve and tube

pounds (18.08 - 21.47 Nm) and secure

assembly from helicopter; and remove tube

with lockwire (CM702).

from relief valve. Reinstall tube assembly on

tee finger tight for storage until required for

NOTE: Clearance differences greater than

replacement of relief valve.

0.032 inch (0.8128 mm) can be reduced by

(3). Remove screw, washer, and clamp, and

re-arranging washers on caliper attach

remove relief valve from canted bulk

bolts.

head 78.50 structure.

(4). To adjust clearances, hold caliper

(4). Install protective caps or plugs on open

assembly and unscrew bolts from

relief valve ports and open ends of

mounting bracket. Transpose washers

disconnected tube assembly to prevent

on bolts as required. Reassemble parts

entrance of contaminants.

and recheck clearances.

B. Hydraulic Relief Valve Installation

NOTE: If new caliper assembly was installed or

Installation procedures are essentially the

if hydraulic fittings were removed from old

reverse of removal procedures, with these

unit, coat all but first two threads of two

special considerations:

bleed screws, tees and plugs with thread

sealant (CM434) or equivalent.

(1). Install new O-ring packing on reducer.

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MAINTENANCE MANUAL

(2). After relief valve is installed and

B. Hydraulic Tube Assembly Installation

connected into the hydraulic system, fill

Tube assembly installation is essentially the

and bleed the system.

reverse of removal procedures, with these

specific considerations.

(3). Reinstall components removed for

access to the hydraulic relief valve.

Consumable Materials

8. Hydraulic Tube Assembly Replacement

(Ref. Section 91−00−00)

Item

Nomenclature

(Ref. Figure 904)

CM418

Cement, epoxy

A. Hydraulic Tube Assembly Removal

(1). Make a straight radial cut into center

The hydraulic tube assembly is attached to the

hole of new grommet and install

main rotor mast pan and to the window

grommet on tube assembly. Position

channel by four clamps. It is connected

parts and bond grommet into slot in air

between tees. The assembly removal requires

baffle with epoxy cement (CM418).

access from the cargo/passenger compartment.

(2). Fill and bleed the hydraulic system.

(1).

Remove attaching screws and both (LH

(3). Reinstall components removed for

and RH) upper forward trim panel

access to the hydraulic tube assembly.

assemblies. Remove convenience panel

cover assembly. Remove attaching

9. Rotor Brake Forward Cover Assembly

screws and transmission cover panel

Installation

assembly.

(Ref. Figure 908)

(2).

Disconnect tube assembly from tees,

(1). Position cover assembly on map case

taking special care to catch any hydrau

assembly with rotor brake handle and

lic fluid that drains or drips from tube

handle retaining clip through cover

assembly or tees when system is

openings. Aft edge of cover must

opened.

overlap forward edge of convenience

panel cover assembly. Install attaching

(3).

Remove (and discard) grommet from

screw through cover assembly and map

tube assembly and air baffle.

case panel into isolation mount on

canted bulkhead 78.50 structure.

(4).

Remove nuts, washers, screws, clamps,

and tube assembly.

(2). On the 369D, secure cover assembly

and doublers to angle assembly with

(5).

If some time is to elapse before re-as

attaching screw. On the 369E/FF,

sembly, install protective caps on open

secure cover assembly to convenience

ends of tees to prevent entrance of

panel, using shims and attaching

contaminants.

screws.

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MAINTENANCE MANUAL

ROTOR BRAKE

INSPECTION/CHECK

When working with hydrau

(5). Verify that clip (Ref. Figure 901) on

WARNING

lic systems, special care

handle retainer assembly holds brake

must be taken to prevent entrance of

handle securely in the stowed (raised)

dust, moisture. and other foreign mate

position.

rial. System contamination can cause

malfunctions that could result in inju

(6). Actuate brake handle to check that

ry to personnel and equipment dam

components of master cylinder linkage

age.

assembly (Ref. Figure 402) operate

freely without binding or excessive play

at pivot points. Verify that spring force

1. Rotor Brake Assembly Inspection

holds lever in BRAKE OFF position.

Consumable Materials

(7). Visually inspect friction surfaces of

(Ref. Section 91−00−00)

brake disc (Ref. Figure 403) for exces

Item

Nomenclature

sive wear, galling, scoring, cracking,

distortion, or other evidence of damage.

CM123

Hydraulic fluid

(8). Rotate the drive system and check that

caliper brake pucks are not dragging on

(1). Visually inspect rotor brake compo

the disc.

nents for general condition, security of

installation, and evidence of hydraulic

(9). Apply sufficient force on brake handle

fluid leakage.

to actuate master cylinder assembly to

pressurize hydraulic system.

NOTE: Excessively low fluid level indicates a

system fault that must be isolated and cor

NOTE: System pressurization (brake actua

rected.

tion) is indicated by the feel of firm resis

tance to handle movement. A cushioned

(2).

Disconnect tube assembly (Ref.

(spongy) feel indicates that the system con

Figure 902) from nipple installed in

tains air which must be removed (bled off)

master cylinder cap. Move end of tube

before proceeding with the inspection.

assembly carefully aside, remove

attaching screws and cap with gasket,

(10). Maintain force on brake handle and

and check that hydraulic fluid level is

verify that pistons in caliper assembly

1/8 - 1/4 inch (3.175-6.35 mm) from top

operate to force brake pucks against

of reservoir. If level is low, add hydrau

friction surfaces of brake disc. Visually

lic fluid (CM123). Take special care to

inspect brake pucks for extent of wear

avoid getting contaminants into the

and evidence of damage.

hydraulic system.

Do not apply a side load to brake

(3).

Visually inspect gasket for tears, cuts,

CAUTION

handle as damage to support

or other damage; replace gasket, if

bracketry may result.

defective. Visually inspect sealing

surfaces of cap and master cylinder

NOTE: Pucks must be extended to the BRAKE

body for nicks, cracks, scratches, or

ON position to permit adequate inspection.

other defects; repair minor damage or

If parting line between piston face and puck

replace defective parts.

is visible, puck is worn excessively and must

be replaced.

(4).

Replace cap and gasket on master

cylinder and secure with attaching

(11). Monitor feel of resistance and increase

screws. Connect tube assembly to

force applied to brake handle until

nipple and tighten tube nut securely.

hydraulic relief valve opens.

Page 601

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MD Helicopters, Inc.

MAINTENANCE MANUAL

NOTE: When working properly, the hydraulic

(15). Raise brake handle to stowed position

relief valve opens and routes pressurized

and engage it in clip on handle retainer

hydraulic fluid back to the master cylinder

assembly.

reservoir when system pressure reaches 500

psig (3447 kPa). Valve opening can be de

2. Rotor Brake Operational Check

tected by a momentary decrease of resis

After rotor brake hydraulic system has been

tance to handle movement. If movement is

filled with fluid, an operational checkout of the

solidly resisted, regardless of force applied,

rotor brake installation must be performed.

the relief valve is defective and must be re

placed.

(1). Start engine, run up rotor to operating

speed, and then make a normal shut

(12). Maintain steady force (just short of that

down (refer to applicable Pilot's Flight

required to initiate relief valve opening)

Manual).

on brake handle and observe handle

movement. Check that actuating lever

Incorrect application of the ro

spacer and master cylinder stop do not

CAUTION

tor brake can result in sudden

contact.

stopping and kick-back of the main rotor, an

action which can cause damage to the rotor

Check for installation of master

CAUTION

blades and strap packs in the rotor hub. Col

cylinder stop to prevent over

lective pitch must never be applied to slow

travel of piston in master cylinder. If stop is

rotor rotation as this can cause damage to

not installed, damage to master cylinder

the rotor blades and strap packs. Applica

components may occur.

tion of a side load to brake handle may dam

NOTE: Continued handle movement indicates

age support bracketry.

the presence of an internal leak condition

(2). When rotor slows to approximately 205

which must be located and corrected.

or less rpm, disengage brake handle

(13). Release force on brake handle and

from retaining clip and pull handle

verify that caliper pistons (and attached

down to apply braking force. Make

brake pucks) are retracted.

certain that collective pitch stick is in

full down position, and that cyclic

NOTE: Failure of pistons to retract indicates

control stick is in neutral position.

that caliper assembly is defective and must

be overhauled or replaced.

(3). Release brake pressure during last

revolution of rotor.

(14). Reinstall components that were

removed for access to the rotor brake

(4). Raise brake handle to stowed position

system.

and engage it in handle retaining clip.

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CSP-HMI-2

MAINTENANCE MANUAL

ROTOR BRAKE

INITIAL INSTALLATION

When working with hydrau

NOTE: A new design convenience panel cover

WARNING

lic systems, special care

assembly (Ref. Figure 908) must be in

must be taken to prevent entrance of

stalled to cover the aft portion of the brake

dust, moisture, or other foreign materi

master cylinder assembly.

al. Hydraulic system contamination

(4). Disconnect electrical wiring and

can cause malfunctions that could re

communications cables from compo

sult in injury to personnel or equip

nents on back of convenience panel

ment damage.

assembly. If cabin heating option is

installed on aircraft, disconnect heated

1. Rotor Brake Initial Installation

air duct from panel-mounted diffuser.

This section provides detailed instructions for

Remove attaching screws and conve

accomplishing initial installation of the rotor

nience panel assembly from aft side of

brake components into the aircraft. In general,

canted bulkhead 78.50 structure.

procedures are applicable to either left hand or

(5). Remove transmission cover panel

right hand command configurations. Where

assembly from fuselage structure.

pertinent, differences are specified.

(6). Cover exposed trim panels to prevent

Illustrations are included to provide data

damage and soiling.

pertinent to aircraft modifications required for

installation of the rotor brake components. All

(7). Remove main transmission from

items and tools required to install the rotor

aircraft (Ref. Sec. 63-20-00/25).

brake are standard and should be procured

locally. Alternate items of comparable charac

(8). Remove tail rotor (Ref. Sec. 64-20-00),

teristics and equal quality may be used.

tail rotor transmission (Ref. Sec.

63-25-10) and tail rotor drive shaft

A. Aircraft Preparation

(Ref. Sec. 63-15-10).

Preparation for installation of rotor brake

C. Removing Components to be Replaced

components include removal of certain original

Certain rotor brake and related components

equipment items to gain access, or for replace

are mounted on the main transmission, and

ment. Preparations also include permanent

are installed in the aircraft as a unit with the

installation of certain rotor brake components.

transmission. Some of these transmission-

B. Installation Access

mounted components replace similar item

counterparts that were used in the original

NOTE: The main transmission must be re

installation.

moved from the aircraft to permit installa

(1). The tail rotor drive coupling installed

tion of the transmission-mounted rotor

on the transmission output shaft must

brake components.

be replaced by a new drive coupling on

(1). Remove both crew compartment and

which the brake disc is mounted.

cargo/passenger compartment doors.

Remove coupling and failsafe device (if

used) from transmission output shaft

(2). Remove crew compartment seats.

(Ref. Sec. 63-15-10). Leave laminated

shim washers on output shaft and

(3). Remove map case assembly from

retain coupling bolt for reassembly use.

forward side of canted bulkhead 78.50

structure. Remove both (LH and RH)

(2). The tachometer generator installed on

upper forward panel assemblies from

the tail rotor cover assembly on main

bulkhead structure. Remove conve

transmission must be replaced by a new

nience panel cover assembly from

unit that provides clearance for the

convenience panel assembly.

rotor brake disc. Remove attaching nuts

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MD Helicopters, Inc.

MAINTENANCE MANUAL

and washers, tachometer generator and

(4). Attach angle assembly to shoulder

gasket from tail rotor cover assembly.

beam with blind rivets.

Retain nuts and washers for re-as

sembly use. Tachometer generator will

E. Master Cylinder Linkage Assembly and

not be reinstalled. Discard gasket.

Mount Bracket Installation

(3). The tail rotor cover assembly is in

(Ref. Figure 901) The master cylinder linkage

stalled on the main transmission

assembly bracket must be installed on canted

housing with nuts and washers in

bulkhead 78.50 vertical member as a means of

stalled on twelve studs. Four of the

attachment for the master cylinder assembly

studs, with special nuts and washers,

and the other components of the master

will be used for installing the rotor

cylinder linkage assembly.

brake caliper mounting bracket.

Remove four nuts and washers (at 1, 2,

Consumable Materials

10, and 11 o'clock positions). These nuts

(Ref. Section 91−00−00)

and washers will not be used at

Item

Nomenclature

reinstallation.

CM318

Primer

D. Angle Assembly Installation (500D)

(Ref. Figure 901) The angle assembly must be

NOTE: Because of its method of attachment, it

installed on canted bulkhead 78.50 shoulder

may be more convenient to install the link

beam as a means of attachment for the

age assembly bracket and then assemble

convenience panel cover assembly and the

the other components on the bracket. Al

rotor brake forward cover assembly.

though the procedures given in steps (1).

thru (3). below consider installation of the

assembly, they are also applicable for instal

Consumable Materials

lation of the bracket. Steps (4). thru (7). be

(Ref. Section 91−00−00)

low describe procedures for assembling com

Item

Nomenclature

ponents to the bracket.

CM318

Primer

(1).

Position master cylinder linkage

assembly on canted bulkhead 78.50

(1). Lay out and mark location for angle

vertical member. Hold assembly (with

assembly on portion of forward bulk

bracket) firmly in position as a guide

head aft panel assembly that covers

and use a No. 15 drill bit to line drill

canted bulkhead 78.50 shoulder beam.

four holes in vertical member, taking

care to prevent point of drill bit from

(2). Insert piece of cardboard (or similar

penetrating into vertical member more

material) under aft panel assembly to

than 1/4 inch (6.35 mm).

protect shoulder beam and use a sharp

knife to make panel cut out to accom

(2).

Line ream holes 0.199-0.202 inch

modate angle assembly, taking special

(5.0546-5.1308 mm) diameter. Remove

care not to cut outside marked area.

linkage assembly, deburr holes in both

parts, and touch up raw metal surfaces

(3). Position angle assembly on shoulder

with primer (CM318).

beam as a guide and drill two

0.128-0.132 inch (3.2512-3.3528 mm)

(3).

Attach bracket to vertical member with

diameter holes through angle assembly

Jo-bolt blind fasteners.

and one wall of shoulder beam, taking

care that point of drill bit does not

(4).

Secure pin (Ref. Figure 402) in bracket

penetrate into shoulder beam more

with nut and washer.

than 1/4 inch (6.35 mm). Deburr holes

in both parts and touch up raw metal

(5).

Install grip on handle. Install new roll

surfaces with primer (CM318).

pins through handle and fitting.

Page 902

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MD Helicopters, Inc.

MAINTENANCE MANUAL

1.00 IN.

(2.54 CM)

0.50 IN.

0.063 IN.

(1.6002 MM)

(12.70 MM)

(STOCK)

1.50 IN.

0.47 IN.

(3.81 CM)

1.00 IN.

(11.938 MM)

(2.54 CM)

0.31 IN.

0.75 IN.

(7.87 MM)

2.00 IN.

(19.05 MM)

(5.08 CM)

2.26 IN.

0.54 IN.

(5.7404 CM)

(13.716 MM)

4.80 IN.

0.38 IN.

(12.192 CM)

(9.652 MM)

1.80 IN.

0.25 IN.

(4.572 CM)

(TYP)

(6.35 MM)

0.70 IN.

(17.78 MM)

0.40 IN.

0.38 IN.

3.07 IN.

0.50 IN.

(10.16 MM)

(9.652 MM)

0.38 IN.

(7.7978 CM)

(12.70 MM)

0.50 IN.

(TYP)

(9.652 MM)

(12.7 MM)

2.38 IN.

4.57 IN.

(6.0452 CM)

(11.6078 CM)

0.32 IN.

0.62 IN.

(8.128 MM)

(15.748 MM)

0.50 IN.

(12.70 MM)

23.80 IN.

(60.452 CM)

HANDLE RETAINER ASSY

G63-2012-2

Figure 901. Locating Permanently Installed Components (Sheet 2 of 2)

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CSP-HMI-2

MAINTENANCE MANUAL

(6). Install bolt, spacer, and nut on lever.

Remove retainer assembly and use a

Attach assembled handle parts to lever,

1/8 inch (3.175 mm) drill bit to drill out

with clevis pin, washers, and new cotter

marked rivets.

pin.

(3). Lay out hole patterns on handle

When parts are assembled,

retainer assembly to match drilled rivet

WARNING

spring force is constantly ex

holes. Use No. 30 drill bit to drill two

erted to inhibit inadvertent brake

holes in retainer.

application. Care must be taken as the

spring is engaged to prevent injury to

(4). Cleco retainer assembly in place. Use

personnel or equipment damage.

retainer as guide and use a No. 15 drill

bit to drill two holes into face of vertical

(7). Install lever with attached parts, and

member. Remove handle retainer

spring on pin and secure with washer,

assembly from vertical member.

nut, and new cotter pin. Engage free

end of spring under head of clevis pin.

(5). Deburr holes and touch up with primer

(CM318).

F. Handle Retainer Assembly Installation

(6). Attach handle retainer assembly to

(Ref. Figure 901) The handle retainer assem

vertical member with four blind rivets.

bly must be installed on canted bulkhead 78.50

vertical member to secure the rotor brake

G. Rivnut Installation

operating handle in the stowed (raised)

position.

(Ref. Figure 902) A rivnut must be installed in

the main rotor mast pan as an attachment

point for one of the clamps used to secure

Consumable Materials

hydraulic tube assembly. For R/H rotor brake

(Ref. Section 91−00−00)

installation, a rivnut must be installed in the

Item

Nomenclature

canted bulkhead 78.50 vertical member for

CM318

Primer

attachment of the hydraulic relief valve.

NOTE: The master cylinder linkage assembly

Consumable Materials

must be installed so that the handle retain

(Ref. Section 91−00−00)

er assembly can be positioned correctly.

Item

Nomenclature

CM318

Primer

(1). Position handle retainer assembly on

canted bulkhead 78.50 vertical member

so that when rotor brake operating

Care must be taken when drill

handle is in the stowed position,

CAUTION

ing the mast pan for rivnut in

retainer clip engages handle just below

stallation to prevent damage to wiring har

the rubber grip.

nesses which are installed on the upper side

of the pan, or to critical structure members

To prevent damage to compo

CAUTION

to which the pan is riveted. A drill stop or

nents, point of drill bit must not

other suitable means should be used to pre

be allowed to penetrate through wall of ver

vent point of drill from penetrating more

tical member more than 1/4 inch (6.35 mm).

than 1/4 inch (6.35 mm) into vertical mem

NOTE: The tunnel beam web is secured to the

ber.

vertical members by a series of rivets. Two

(1). Lay out location for hole in transmis

of these rivets must be removed and re

sion pan. Use 1/4 inch (6.35 mm) drill

placed by rivets that also attach the handle

retainer assembly.

bit to drill hole through pan, deburr

hole, and touch up raw metal surfaces

(2). Mark two rivets on front of vertical

with primer (CM318). Install rivnut in

member that most closely match

accordance with standard shop practice

position of handle retainer assembly.

and manufacturer's instructions.

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MD Helicopters, Inc.

MAINTENANCE MANUAL

(2). Lay out location for hole in vertical

in tail rotor cover assembly for use as

member. Use 1/4 inch (6.35 mm) drill

spacers. Position caliper mounting

bit to drill hole through outer face of

bracket on studs and secure with

vertical member. Deburr hole and touch

washers and nuts. Torque nuts to 50 -

up raw metal surfaces with primer.

70 inch-pounds (5.65 - 7.91 Nm).

Install rivnut in accordance with

standard shop practice and manufac

(2). Secure installation with lockwire

turer's instructions.

(CM702).

H. Window Support Channel Modification

J. Caliper Assembly, Brake Disc and Drive

Coupling Installation

(Ref. Figure 903) Three clamps are used to

attach hydraulic tube assembly to the window

(Ref. Figure 902) The caliper assembly is

support channel. Modifications to the channel

bolted to a mounting bracket which is installed

are required to accommodate two of the

on the main transmission tail rotor cover. The

clamps.

brake disc is bolted on the drive coupling

which is installed on the transmission output

shaft. For clarity, the brake disc and drive

Consumable Materials

coupling are considered as a single item,

(Ref. Section 91−00−00)

herein referred to as the disc/coupling unit.

Item

Nomenclature

Although the caliper assembly and the

CM318

Primer

disc/coupling unit are not mechanically

connected, they are installed on the transmis

sion with the outer portion of the disc posi

(1). Use 1/8 inch (3.175 mm) drill bit to

tioned between the two halves of the caliper

remove one (3rd rivet from front) of the

assembly. This arrangement makes it neces

four rivets used to attach forward

sary to install both units at the same time.

nutplate angle clip to channel. Enlarge

hole to 0.188-0.218 inch (4.7752-5.5372

Consumable Materials

mm) with 3/16 inch (4.7625 mm) drill

(Ref. Section 91−00−00)

bit, deburr hole, and touch up raw

Item

Nomenclature

metal surfaces with primer (CM318).

CM113

Anti-seize compound low temperature

(2). Lay out location for hole in channel as

CM117

Grease

shown. Use 3/16 inch (4.7625 mm) drill

CM434

Thread sealant

to drill hole in channel, deburr hole,

and touch up raw metal surfaces with

CM702

Lockwire CRES

primer.

Axial positioning of the

I. Caliper Mounting Bracket Initial

WARNING

drive coupling is critical as

Installation

it controls the mechanical interface be

(Ref. Figure 902) The caliper mounting bracket

tween the coupling and the tail rotor

is installed on four of the twelve studs used to

drive shaft. Excessive axial loads can

secure the tail rotor cover assembly on the

contribute to coupling failure which

main transmission housing.

could result in injury to personnel or

equipment damage. Refer to Section

63-15-10 for shimming procedures for

Consumable Materials

installing coupling disc on shaft.

(Ref. Section 91−00−00)

Item

Nomenclature

NOTE: Before installing caliper, brake disc and

CM702

Lockwire CRES

drive coupling, install new tachometer gen

erator and gasket. Ensure that mechanical

drive components are correctly engaged and

(1). Place three washers on each of the four

electrical receptacle is at the 11 o'clock posi

studs (1, 2, 10, and 11 o'clock positions)

tion.

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CSP-HMI-2

MAINTENANCE MANUAL

369D23012-5 REF

369D23012-13 REF

G63-2019

Figure 903. Modifying Window Support Channel

(1).

Measure (with a micrometer) and

on tees, and install bleed screws in

record thickness of brake disc at four

adapters. Remove and discard hard

locations around the disc. Calculate and

ware used to hold caliper halves

record average of thickness measure

together.

ments.

NOTE: The caliper assembly consists of two

(2).

Position brake disc on tail rotor drive

identical halves. When received, the halves

coupling with raised center side of disc

are held together by commercial hardware.

seated firmly on shoulder of coupling

This hardware is replaced by qualified stan

and with bolt holes aligned. Secure disc

dard hardware which also secures the cali

to coupling with attaching hardware

per assembly on the mounting bracket.

and torque nuts (in an alternating

sequence) to 100 - 140 inch-pounds

(5). Insert bolts through one caliper half,

(11.30 - 15.82 Nm).

position assembled parts of mounting

bracket and screw bolts into bracket

(3).

Measure (with an inside micrometer)

finger tight to maintain alignment of

and record gap between brake puck

caliper half. Use a C-clamp or other

faces. Subtract brake disc thickness

suitable means to clamp caliper half

calculated in step (1). from gap mea

firm against bracket.

surement and divide the difference by

two to determine the optimum puck-to-

(6). Coat, completely but sparingly, splines

disc clearance.

of transmission output shaft with

(4).

Remove bleed screws from ports in ends

grease (CM117) and threads of coupling

of caliper assembly. Coat all but first

with anti-seize compound (CM113), or

two threads of bleed screws, tees, and

equivalent. Install coupling/disc unit on

plugs with thread sealant (CM434).

shaft and install bolt into end of shaft

Install plugs in bleed screw ports and

to ensure that coupling is seated firmly

tees in caliper bodies, install adapters

against shim washers on shaft.

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MD Helicopters, Inc.

MAINTENANCE MANUAL

TUBE ASSY

BAFFLE ASSY

MAST SUPPORT

PAN

GROMMET

NOTE:

CHANNEL ASSY

LEFT-HAND INSTALLATION

G63-2020

RIGHT-HAND OPPOSITE

Figure 904. Hydraulic Tube Installation

The caliper assembly must

NOTE: Fore-and-aft positioning of the caliper

WARNING

be installed so that caliper-

assembly, which determines the puck-to-

to-disc clearances on both sides of disc

disc clearance relationship, is established by

are approximately equal. Improper in

installing shim washers between the caliper

stallation can cause malfunctions

assembly and the mounting bracket. Nine

which could result in injury to person

washers are provided for each attaching

nel or equipment damage.

bolt; those not required for shimming must

be installed under the bolt heads.

(7). Measure gap between brake caliper

(8). Remove bolts and place the correct

housing and forward face of disc with a

number (nine less the number required

thickness gage. Subtract desired

for shimming) of washers on each bolt.

caliper-to-disc clearance calculated in

Insert bolts through caliper halves and

step (3). from this measurement to

screw one bolt finger tight into mount

determine amount of shimming (wash

ing bracket. Release clamped caliper

ers) to be installed between caliper

half and move it away from bracket,

assembly and mounting bracket. Divide

place required number of shim washers

the difference by 0.032 inch (0.8128

on second bolt as it is pushed through

mm) (washer thickness) to determine

caliper assembly, and screw bolt into

number of shim washers needed.

bracket a few turns. Repeat procedure

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CSP-HMI-2

MAINTENANCE MANUAL

to install shim washers on other bolt.

Tighten bolts firmly to secure installa

4389 GRIP

tion.

(1 REQD)

(9). Check caliper-to-disc clearances with a

thickness gage. If clearances are

approximately equal, torque mounting

bolts to 160 - 190 inch pounds (18.08

- 21.47 Nm) and secure with lockwire

(CM702). Torque coupling bolt to 250 -

300 inch-pounds (28.25 - 33.90 Nm)

plus drag torque.

MASTER

CYLINDER

(10). After the rotor brake components have

been installed on the main transmis

sion, the built-up unit must be in

stalled in the aircraft (Ref. Sec.

0.02 IN. (0.508 MM)

GAP

0.04 IN. (1.016 MM)

63-20-00/25).

The main transmission must

WARNING

be installed in the aircraft

with special care to avoid damage to

rotor brake components. Installation

G63-2022A

damage could lead to system failure

which could result in injury to person

Figure 905. Positioning Master Cylinder

nel or equipment damage.

(3). Install new cap and reworked gasket on

master cylinder with attaching screws

(11). If tachometer generator is installed on

transmission, connect electrical plug

installed finger tight.

(P202) on aircraft wiring harness to

(4). Coat all but first two tapered pipe

receptacle on tachometer generator.

threads of nipples and elbow with

thread sealant (CM434). Install nipples

K. Master Cylinder Assembly Initial

in cap and elbow in master cylinder.

Installation

(5). Place one washer on each bolt, place

(Ref. Figure 902) The master cylinder assem

stop on bolts and insert bolts through

bly is mounted on the master cylinder linkage

master cylinder. Place two washers on

assembly bracket.

each bolt as spacers. Position as

sembled parts on linkage assembly

bracket and secure installation with

Consumable Materials

washers and nuts. Tighten nuts only

(Ref. Section 91−00−00)

finger tight.

Item

Nomenclature

NOTE: Mounting holes in bracket are elon

CM434

Thread sealant

gated to enable lateral position adjustment

of master cylinder assembly.

(1). Remove attaching screws and vendor-

(6). With actuating handle in stowed

supplied cap from master cylinder.

position, adjust position of master

Vendor cap is not used.

cylinder assembly so that clearance

(measured with a thickness gage)

(2). Rework vendor-supplied gasket (Ref.

between actuating lever (Ref.

Figure 906).

Figure 905) and master cylinder piston

Page 911

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CSP-HMI-2

MD Helicopters, Inc.

MAINTENANCE MANUAL

is 0.020-0.040 inch (0.508-1.016 mm).

ing hardware loosely to hold clamps

Tighten nuts to hold master cylinder

(and tube assembly) to pan and window

assembly firmly in position.

channel.

L. Hydraulic Relief Valve Initial Installation

(4). Connect tube assembly loosely to elbow

in master cylinder and to tee.

(Ref. Figure 902) The hydraulic relief valve is

attached by means of a clamp to the canted

(5). With all tube assemblies and fittings

bulkhead 78.50 vertical member, and is

connected, tighten nuts on tube assem

connected hydraulically, by means of tube

blies. Tighten attaching hardware for

assemblies, between the master cylinder

all clamps.

assembly and the caliper assembly.

NOTE: It is not necessary to tighten tube as

(1). Place new O-ring on reducer and screw

sembly nuts at this time. The tube assembly

reducer into relief valve. Connect relief

will have to be removed to permit filling the

valve to tube assembly and tighten tube

hydraulic system.

nut. Install clamp on relief valve.

(6). Connect tube assembly to nipple in

(2). Position assembled parts with relief

master cylinder cap and tighten tube

valve in ``V'' of handle retainer assem

nut.

bly. Install attaching hardware loosely

N. Rotor Brake Installation Servicing

to hold assembled parts on canted

bulkhead 78.50 vertical member.

After all operating components of the rotor

brake system have been installed, the hydrau

NOTE: Screw is threaded into nutplate for LH

lic system must be filled with hydraulic fluid

installation, and into rivnut for RH installa

and have all entrapped air bled off. Refer to

tion.

Rotor Brake Hydraulic System Bleeding.

M. Hydraulic Tube Assemblies Initial

Installation

0.50 IN. (12.70 MM) DIA.

0.56 IN.

(Ref. Figure 902) Two tube assemblies are

(14.224 MM)

installed to connect the master cylinder

assembly and the caliper assembly.

Consumable Materials

(Ref. Section 91−00−00)

Item

Nomenclature

CM418

Cement, epoxy

(1). Connect tee loosely to tube assembly.

Make straight radial cut into center

hole of grommet and install grommet

and clamps on tube assembly.

(2). Position assembled parts on window

channel so that grommet can be

engaged in slot of air baffle. Connect

tube assembly loosely to tee on caliper

assembly and connect tee loosely to

EXISTING HOLES

tube assembly on hydraulic relief valve.

G63-2021A

(3). Bond grommet into air baffle slot with

Figure 906. Reworking Master Cylinder

epoxy cement (CM418). Install attach

Gasket

Page 912

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CSP-HMI-2

MAINTENANCE MANUAL

O. Installing Interior Furnishings

to be drilled on rotor brake forward

cover panel.

After the operating components of the rotor

brake installation have been checked out, the

(3). Use No. 42 drill bit to drill holes at

various items of interior furnishings (trim

marked location for attaching screws.

panels, cover assemblies, seats, etc.) and the

fuselage doors must be reinstalled. This

NOTE: It may be more convenient to remove

includes those items that are specific for the

convenience panel cover assembly while

rotor brake installation, and those that were

drilling hole.

removed to permit access for installing the

rotor brake components.

(4). On the 5000D, secure convenience

panel cover assembly with doublers to

P. Map Case Assembly Modification and

angle assembly with attaching screw.

Installation

On the others, the convenience panel

cover assembly will be permanently

(Ref. Figure 907) Before the map case assem

fastened down when mated with the

bly can be reinstalled, it must be modified to

rotor brake forward cover assembly.

accommodate the rotor brake forward cover

assembly.

R. Rotor Brake Forward Cover Assembly

Installation

(1). Mark map case panel for cutout. Use a

sharp knife to cut out marked area,

(Ref. Figure 908) The rotor brake forward

taking special care to avoid cutting

cover assembly mates with the convenience

outside of marked area.

panel cover assembly to enclose and protect

the rotor brake components (master cylinder,

(2). Install map case assembly on canted

etc.) installed on the canted bulkhead 78.50

bulkhead 78.50 structure with three

structure. It is installed over the forward

attaching screws.

portion of the master cylinder assembly and

incorporates cutouts to accommodate the

NOTE: A fourth screw will also be used to at

brakes handle and retaining clips.

tach the rotor brake forward cover assembly

(Ref. Figure 908).

(1). Position rotor brake forward cover

assembly on map case assembly with

Q. Convenience Panel Cover Assembly

aft edge overlapping forward edge of

Modification and Installation

convenience panel cover assembly and

(Ref. Figure 908) The convenience panel cover

with brake and retaining clips extend

assembly mates with the rotor brake forward

ing through cutouts.

cover assembly to enclose and protect the rotor

brake components installed on the canted

NOTE: If aircraft is equipped with optional

bulkhead 78.50 structure.

particle separator, it may be necessary to

trim the forward cover assembly for clear

(1). Position new convenience panel cover

ance.

assembly with the aft edge overlapping

the forward edge of the transmission

(2). On the 500D, mark location for hole in

cover panel. Install attaching screws to

upper corner of forward cover assembly

hold panels in position.

to line up with isolator mount, and in

lower corner to line up with nutplate in

(2). On the 500D, mark location for hole in

angle assembly on canted bulkhead

the forward corner of convenience panel

78.50 shoulder beam. On the others,

cover assembly to line up with nutplate

mark location for hole in upper corner

on angle assembly on canted bulkhead

of forward cover assembly to line up

78.50 shoulder beam. On the others,

with isolator mount and in upper and

mark location for holes in forward

lower outboard corners to line up

corner of convenience panel cover

parallel with holes previously drilled in

assembly to line up parallel with holes

the convenience panel cover assembly.

Page 913

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

(3). Use No. 42 drill bit to drill holes at

the outboard edge of forward cover

marked locations for attaching screws.

assembly and convenience panel cover

assembly.

NOTE: It may be more convenient to remove

(5). Push panel boot aft on brake handle

forward cover panel assembly while drilling

approximately 2 inches (5.08 cm) and

holes.

secure boot fastener tape.

(4). Secure forward cover assembly and

S. Weight and Balance

map case panel assembly with attach

ing screws. On the 500D, install screw

(Ref. Table 901) After installing the rotor

through nutplate in angle assembly. On

brake, incorporate changes in helicopter

the others, install screws into shims on

weight and balance record.

Table 901. Weight and Balance Data

Configuration

Weight

Arm

Moment

(kg)

in.

(cm)

in−lb (kg−cm)

500D (left side)

Added

+7.5 (+3.40)

106.6

(270.764)

+800 (9216.96)

Removed

0.0

−

0.0

Changed

+7.5 (+3.40)

106.6

(270.764)

+800 (9216.96)

500D (right side)

Added

+6.8 (3.08)

108.9

(276.606)

+741 (8537.21)

Removed

0.0

−

0.0

Changed

+6.8 (3.08)

108.9

(276.606)

+741 (8537.21)

369E/FF − 500N (left and right)

Added

+7.5 (+3.40)

106.5

(270.51)

+799 (9205.44)

Removed

0.0

−

0.0

Changed

+7.5 (+3.40)

106.5

(270.51)

+799 (9205.44)

600N (left and right)

Added

+7.6 (+3.45)

98.4

(294.44)

+748 (862.3)

Removed

0.0

−

0.0

Changed

+7.6 (+3.45)

98.4

(294.44)

+748 (862.3)

Page 917

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MD Helicopters, Inc.

CSP-HMI-2

MAINTENANCE MANUAL

TAIL ROTOR TRANSMISSION (TWO AND FOUR BLADE)

MAINTENANCE PRACTICES

1. Tail Rotor Transmission

Do not carry or otherwise sup

CAUTION

port transmission by coupling,

(Ref. Figure 201) The tail rotor transmission is

as coupling diaphragm may be permanently

a right-angle transmission with a magnesium

distorted. During performance of all mainte

alloy housing. A magnetic chip detector is

nance on transmission, use extra care to

located on the aft end of the transmission, a

keep contaminants such as paint, dirt, etc

breather-filler is located on the top and a sight

from areas around input and output shaft

gage is mounted on the aft end (two-bladed) or

seals.

on the right side (four-bladed) of the transmis

sion.

(1). Install tail rotor drive shaft on tail rotor

transmission (Ref. Sec. 63-15-10).

2. Tail Rotor Transmission Replacement

(Ref. Figure 203) Ensure securi

CAUTION

A. Tail Rotor Transmission Removal

ty of tail rotor transmission

mount studs. Maximum allowable side play

(1). Disconnect tail rotor driveshaft from

at end of stud is 0.004 inch (0.102 mm),

transmission (Ref. Sec. 63-15-10).

maximum allowable axial play is 0.005 inch

(0.127 mm). For stud replacement, refer to

(2). Disconnect chip detector wire.

the Structural Repair Manual (SRM).

(3).

(369D/E) Remove four nuts and

NOTE: Ensure all paint and sealant is removed

washers from transmission mount

from mating surfaces. Remove excessive

studs.

sealant, as required, from transmission to

gain clean mounting surfaces. Ensure that

(4).

(369FF) Remove four bolts, eight

no gap in sealant coverage exists around the

washers and four nuts between trans

transmission bearing cover assembly.

mission and tailboom extension.

(2). Visually inspect mounting studs for

NOTE: Retain any shimming washers that

damage or deformation. Replace

may be between tail rotor transmission and

damaged or deformed stud (Ref. SRM).

tail boom for transmission installation.

(3). Apply primer (CM318) in holes and on

(5). With assistance, support transmission

the grip area of the mounting studs.

and shaft in line for minimum deflec

Install tail rotor transmission or

tion of coupling and remove tail rotor

tailboom extension while primer is still

drive shaft and transmission as a unit.

wet.

(6). Remove tail rotor from tail rotor

(4). With assistance, support transmission

transmission (Ref. Sec. 64-20-00).

and shaft in line for minimum deflec

tion of coupling and install tail rotor

(7). Remove tail rotor drive shaft from tail

drive shaft and transmission as a unit

rotor transmission (Ref. Sec.

(Ref. Sec. 63-15-10).

63-15-10).

NOTE: Note the drag torque for each nut and

B. Tail Rotor Transmission Installation

it's location on the transmission in the heli

copter for later use.

Consumable Materials

(a).

(369D/E) Secure tail rotor transmis

(Ref. Section 91−00−00)

sion to four tailboom mounting studs

Item

Nomenclature

with washers and nuts. Torque nuts

CM318

Primer

to 75 - 95 inch-pounds (8.47 -

10.73 Nm) plus drag torque.

Page 201

63-25-10

TR13-001

HANDBOOK OF MAINTENANCE INSTRUCTIONS FOR MDHI 369D/E/FF-500/600N HELICOPTERS (ISSUED: 1990) - page 21