Rolls-Royce Engine 250–C18, 250–C18A, 250–C18B, 250–C18C. Operation and Maintenance Manual (2003) - page 11
Legend for FIG. 83 (Sheet 1 0f 2)
1. Nozzle
22. Retaining ring
2. Nut (2)
23. Roller bearing
3. O-ring
24. Thrust washer
4. Gearbox cover
25. O-ring
5. Nut (36)
26. Power train drive helical gear
6. Bolt
27. Internal retaining riing
7. Bolt
28. Ball bearing (2)
8. Washer (38)
29. Internal retaining ring
9. Nut (3)
30. Fuel control spur gearshaft
10. Washer (3)
31. Internal retaining ring
11. Bolt (2)
32. Pin
12. Washer (2)
33. Splined adapter
13. Spanner nut
34. O-ring
14. Key washer
35. Internal retaining ring
15. Cup washer
36. Bearing retainer
16. Torquemeter shaft support
37. Ball bearing (2)
17. Pin
38. Bearing spacer
18. Power Takeoff Helical gearshaft
39. Identification plate
19. Roller bearing
40. Screw (2)
20. Ball bearing
41. Washer (2)
21. Torquemeter helical gearshsft
Page 227
Power and Accessories Gearbox Cover Assembly (Sheet 2 of 2)
FIG. 83
Page 228
Legend for FIG. 83 (Sheet 2 0f 2)
1. Accessory drive spur gearshaft
19. Bolt (3)
2. Plug
20. Key washer (3)
3. Starter generator spur gearshaft
21. Keyway washer (3)
4. Plug
22. Internal retaining ring
5. O-ring
23. Ball bearing (3)
6. Fuel pump drive spur gearshaft
24. Idler gear support shaft (3)
7. Internal retaining ring
25. Oil transfer tube
8. Drilled plug
26. O-ring (2)
9. Internal retaining ring
27. Accessory pad seal
10. Bearing retainer
28. Accessory pad seal
11. Ball bearing
29. Accessory pad seal
12. Spacer
30. Qick disconnect mag plug
13. Spacer
31. O-ring
14. Gas producer gear train idler
32. Flanged insert
spur gearshaft
33. Pin
15. Ball bearing
34. O-ring
16. Ball bearing
17. Internal retaining ring
18. Gas producer gear train idler
spur gear (3)
Page 229
Torquemeter Shaft Support Spanner Nut Removal or Installation
FIG. 84
Torquemeter Shaft Support
FIG. 85
Page 230
Roller Bearing Inner Race from the Torquemeter Shaft Support Removal
FIG. 86
Ball Bearing from the Helical Power Takeoff Gearshaft Removal
FIG. 87
Page 231
Fuel Control Spur Gearshaft Removal
FIG. 88
Fuel Control Spur Gearshaft Components
FIG. 89
Page 232
(9)
Remove the accessory drive spur gearshaft (spare) from the gearbox cover by removing the
internal retaining ring with 6796966 pliers.
(Ref. FIG. 83, Sheet 2 of 2, and 90) Remove the
retaining ring and bearing retainer. Remove the bearings and spacer from the shaft using
6796946 drift and 6796950 plate with detail -12.
NOTE: Do not remove the plugs from the spur gearshafts unless they are loose. If
replacement is necessary, press out plugs with a 5/8 in. (16 mm) OD drift.
(10) Remove the starter generators spur gearshaft from the gearbox cover by removing the internal
retaining ring with 6796966 pliers. Discard O-ring. (Ref. FIG. 90) Remove the retaining ring
and bearing retainer. Remove the bearings and spacer from the shaft using a 6796946 drift
and 6796950 plate with detail -12.
(11)
Remove the fuel pump drive spur gearshaft from the gearbox cover by removing the internal
retaining ring with 6796966 pliers. (Ref. FIG. 90) Remove the retaining ring and bearing
retainer. Remove the bearings and spacer from the shaft using 6796946 drift and 6796950
plate with detail -12.
(12) Unlock the key washers and remove the two exposed bolts, key washers, and keyway
washers from the gas producer gear train idler spur gears. Remove the two gears and
bearings from the idler gear support shafts. Remove the bearings from the idler gears by
removing the internal retaining rings. (Ref. FIG. 91)
(13) Unlock the key washer of the gas producer gear train idler spur gear beneath the gear train
idler gearshaft. Remove the idler gearshaft bolt, washer, and key washer as the gear train
idler gearshaft is being lifted out.
(14) Remove the internal retaining ring. Remove the bearing from the cover end of the gearshaft
using 6796946 drift and 6796950 plate with detail -8. Remove the bearing from the housing
end of the gearshaft using 6796946 drift and 6796950 plate with detail -13. Remove the gear
and bearing from the idler gear support shaft. Remove retaining ring and separate bearing
from gear.
(15) Remove the three idler gear support shafts from the gearbox cover using 6795614 puller and
pusher. (Ref. FIG. 92)
(16) Remove the oil transfer tube and O-rings from the gearbox cover. Discard O-rings.
(17) Remove lockwire and separate the magnetic plug from the gearbox cover. Discard packing.
(18) Use 6796941 seal replacement kit to replace defective gearbox cover seals.
Page 233
Accessory Drive Spur Gearshaft Removal or Installation
FIG. 90
Idler Spur Gear Retaining Ring Removal or Installation
FIG. 91
Page 234
Idler Spur Gear Support Shaft Removal or Installation
FIG. 92
C. Disassemble the gearbox housing as follows:
(1) Remove the fuel control and oil pump spur gearshaft. (Ref. FIG. 93) Remove the bearings
using 6796946 drift and 6796950 plate with details -13 and -14. Rotate bearings during
removal to avoid brinelling the raceways.
(2) Remove the tachometer and governor power train spur gearshaft. Remove the bearings using
6796946 drift and 6796950 plate with details -7 and -12. Do not remove the spring pin.
(3) Unlock the key washer and remove the power train idler spur gear bolt, key washer, and
keyway bearing retaining washer. Lift the gear and bearing from the idler gear support shaft.
Pull the shaft from the gearbox housing using 6795614 puller and pusher. (Ref. FIG. 94)
Remove the bearing from the gear by removing the internal retaining ring.
(4) Lift the helical power takeoff gearshaft roller bearing outer race and rollers from the gearbox
housing.
Page 235
1. Fuel control and oil pump spur gearshaft
13. Idler gear support shaft
2. Ball bearing (2)
14. Roller bearing
3. Power train tachometer and governor spur
15. Torquemeter support shaft nut
gearshaft
16. Internal flared washer
4. Spring pin
17. O-ring
5. Ball bearing
18. Torquemeter support shaft
6. Ball bearing
19. O-ring
7. Power train idler spur gear
20. Torquemeter piston
8. Bolt
21. Ball bearing
9. Key washer
22. Piston ring
10. Keyway washer
23. Expander ring
11. Internal retaining ring
24. Roller bearing
12. Ball bearing
25. Flat washer
Power and Accessories Gearbox Housing Assembly
FIG. 93
Page 236
(5) Remove lockwire then remove the torquemeter support shaft nut using 6795597 wrench and
6795974 aligning fixture. (Ref. FIG. 95 and 96) Remove O-ring and washer. Discard the
O-ring. Remove the shaft. Remove the torquemeter support shaft bearing end plate and
washer from the gearbox housing. Remove and discard O-ring from the shaft. Remove
piston and bearing from the shaft. Remove the expander and piston ring. Remove the ball
bearing from the piston using 6796947 drift and 6796950 plate with detail -6. Remove the
bearing outer race and rollers from the support shaft. Remove the bearing inner race from the
support shaft using 6796947 drift and 6796950 plate with detail -4.
Idler Gear Support Shaft Removal or Installation
FIG. 94
Page 237
Torquemeter Support Shaft Spanner Nut Removal or Installation
FIG. 95
Torquemeter Support Shaft Aligning Fixture
FIG. 96
Page 238
123. Gearbox Housing Lubrication System Components Maintenance
A.
Disassemble the gearbox housing lubrication system components as follows:
(1)
Remove the two nuts, washers, oil filter cap, oil filter and O-ring from the filter housing. (Ref.
FIG. 97, Sheet 1 of 2.) Discard the O-ring.
(2)
Remove the eight nuts and washers and lift the lube oil filter housing from the gearbox
housing. Discard the gasket.
(3)
Remove the lockwire and remove the pressure regulator components from the filter housing.
These components are: (1) poppet guide, (2) O-ring, (3) spring, and (4) poppet.
(4)
Remove the internal retaining ring and the filter bypass components from the filter housing.
These components are: (1) poppet guide, (2) O-ring, (3) spring, and (4) poppet.
NOTE: Do not remove the studs, standpipe, or two valve seats.
(5)
Remove the screw and separate the oil pressure tube from the gearbox housing. Discard the
O-ring.
(6)
Remove the screw and separate the oil delivery tube from the gearbox housing. Remove the
screen and discard the three O-rings.
(7)
Remove the three oil transfer tubes. Discard two O-rings from each tube.
(8)
Remove the screw retaining the scavenge oil pickup tube. Do not remove the tube until the
pump is removed (step k).
(9)
Remove the check valve. (Ref. FIG. 97, Sheet 2 of 2.) Remove and discard the two O-rings.
Do not disassemble the check valve.
(10) Remove the fuel control and oil pump flex shaft coupling.
(11)
Remove the eight pump attaching screws and six washers. Remove the oil filter inlet and
bypass tubes. Discard two O-rings from each. Remove the pump and the scavenge oil
pickup tube. Discard the O-ring from the tube. Discard the gasket and O-ring beneath the
pump. Do not disassemble the pump.
(12) Remove the oil transfer tube and connector beneath the oil pump. Discard two O-rings from
each.
(13) Remove the lockwire and separate the magnetic plug from the gearbox housing. Discard
packing.
(14) Remove gearbox housing accessory pad seals using 6796941 seal replacement kit only if the
seals are defective.
B.
OIL FILTER INLET TUBE ASSEMBLY DROP DIMENSION INSPECTION
(1) Engines that exhibit low or fluctuating oil pressure may have been assembled with an
incorrectly manufactured tube assembly, P/N 6876925A. If the gearbox modification log card
does not show compliance with 250-C18 CEB 274, proceed to the next step.
(2) Remove the lube oil filter housing assembly from the gearbox. Refer to para 120A.
(3) Make sure that all gasket material is removed from the gearbox. Do not let gasket material or
other foreign material fall into the gearbox.
(4) Using a 2-3 inch depth micrometer, measure the distance from the gearbox/filter housing
splitline to the top of the oil filter inlet tube assembly, P/N 6876925A. (Ref. FIG. 98)
(5) If this dimension exceeds 2.843 in. (72.21 mm), then the oil inlet tube assembly and the oil
filter housing assembly may not be correctly engaged. Reject the gearbox for compliance of
250-C18 CEB 274 or replace P/N 6876925A, Oil Filter Inlet Tube Assembly with P/N
6876925B (or later) Oil Filter Inlet Tube Assembly.
Page 239
Gearbox Housing Lube System Assembly (Sheet 1 of 2)
FIG. 97
Page 240
Legend for FIG.87 (Sheet 1 of 2)
1.
Oil filter cap
21. Flanged bushing (3)
2.
Nut (2)
22. Stud (2)
3.
Washer (2)
23. Standpipe
4.
O-ring
24. Valve seat (2)
5.
Filter
25. Gasket
6.
O-ring
26. Oil pressure tube
7.
Filter housing
27. Screw
8.
Nut (8)
28. O-ring
9.
Washer (8)
29. Oil delivery tube
10.
Decal
30. Screw
11.
Poppet guide
31. O-ring (2)
12.
O-ring
32. O-ring
13.
Spring
33. Screen
14.
Poppet
34. Oil transfer tube (2)
15.
Internal retaining ring
35. Oil transfer tube
16.
Poppet guide
36. O-ring (6)
17.
O-ring
37. Oil scavenge pickup tube
18.
Spring
38. Screw
19.
Poppet
39. O-ring
20.
Filter housing
Page 241
Gearbox Housing Lube System Assembly (Sheet 2 of 2)
FIG. 97
Page 242
Legend for FIG. 97 (Sheet 2 of 2)
1. Check valve
17. Screw (2)
2. Retaining ring
18. Washer (6)
3. Guide (2)
19. Gasket
4. Spring
20. Packing
5. Poppet assembly
21. Packing (6)
6. Poppet
22. Oil transfer tube
7. Stem
23. Connector
8. Body
24. Packing (2)
9. Packing
25. Seal (2)
10. Packing
26. Seal
11. Flex shaft coupling
27. Gearbox housing
12. Filter inlet tube
28. Quick disconnect mag plug
13. Filter bypass tube
29. Packing
14. Oil pump
30. Insert
15. Screw (5)
31. Pin
16. Screw
32. Packing
Page 243
Oil Filter Inlet Tube Assembly Drop Dimension Inspection
FIG. 98
Page 244
C.
Oil Pump Maintenance
(1)
Disassemble and inspect the oil pump when it is the suspected cause of oil pressure and/or oil
scavenging discrepancies. Remove pump in accordance with the Gearbox Housing
Lubrication System Components. Install pump in accordance with the Gearbox Assembly.
(2)
Disassemble the lube pump as follows: (Ref. FIG. 99)
CAUTION: BE CAREFUL NOT TO PRY ON, OR DAMAGE, ANY LAPPED SURFACES.
(a) Remove two screws and use a prying tool to separate the pressure oil pump body from
the balance of the pump.
(b) Remove the oil pump idler spur gear. Remove and discard the O-ring in the pump body.
Do not remove the pinned bushing cage or flanged bushings unless replacement is
required.
(c) Remove the oil pump and gas producer tachometer spur gearshaft. Do not remove the
oil seal plug unless it is loose. If replacement is necessary, press out the plug using
1/4-in. (6 mm) OD drift.
(d) Remove the pressure and scavenge oil pump separator body and scavenge oil pump
cover from the scavenge oil pump body using a prying tool. Do not pry on lapped
surfaces. Do not remove the three pinned oil pump gearshafts or the pinned bushing
from the scavenge oil pump cover. Remove and discard two O-rings from separator
body.
(e) Remove the oil pump drive spur gear, three idler spur gears, the pump drive spur gear,
and the idler spur gear from the scavenge oil pump body. Remove and discard two
O-rings from the pump body. Do not remove the four dowel pins from the pump body
unless replacement is necessary.
(3)
Inspect the components of the oil pump in accordance with Table 18.
(4)
Replace or secure loose oil pump gearshafts as follows:
(a) Immediately prior to installing gearshafts, clean the bores and the gearshaft using
cleaning agent recommended by Loctite Corporation. Apply Loctite 290, in accordance
with Loctite Corporation recommendations, to the mating surfaces of the gearshaft OD
only.
(b) Install gearshaft with the slot aligned with the anti-rotation pin and ensure that it bottoms
in the cover assembly bore.
(c) Immediately after gearshaft installation, clean off any Loctite on the shaft OD and cover
assembly.
(5)
Assemble the lube oil pump as follows: (Ref. FIG. 99)
CAUTION: USE ONLY SPECIFIED LUBRICANTS DURING PUMP ASSEMBLY; DO NOT USE
SILICONE LUBRICANTS.
(a) Lubricate and install the two O-rings in the scavenge body assembly. Install the oil pump
drive gear and three oil pump idler gears.
1
Measure the gear end clearance in the pressure and scavenge elements between
the splitline and gear end with a dial indicator. The gear end clearance must be
0.0005-0.0015 in. (0.013-0.038 mm).
2
If the end clearance limit is exceeded, select gears or lap scavenge oil pump body,
pressure and scavenge oil pump separator body or pressure oil pump body as
necessary to obtain required gear end clearance. Ensure that lapping is done on a
flat lap surface and that the whole face of the item being lapped is smooth and
square. Surface finish after lapping must be 32 micro inches or better.
Page 245
1. Pressure oil pump body
15. Oil pump gearshaft
2. Screw (2)
16. Oil pump gearshaft (2)
3. Pin
17. Pin
4. Bushing
18. Bushing
5. Pin
19. O-ring
6. Flanged bushing (2)
20. O-ring
7. Bearing cage
21. Scavenge oil pump body
8. Oil pump idler spur gear
22. Pin (2)
9. O-ring
23. Pin (2)
10. Oil pump and gas producer
24. Oil pump drive spur gear
tachometer spur gearshaft
25. Oil pump idler spur gear (3)
11. Plug
26. Oil pump drive spur gear
12. Pressure and scavenge oil pump seperator
27. Oil pump idler spur gear
body
28. O-ring
13. Scavenge oil pump cover
29. O-ring
14. Pin (3)
Oil Pump Assembly
FIG. 99
Page 246
TABLE 18
Oil Pump Inspection Limits
Item Condition
Serviceable Limit
Repairable Limit
Disposition
Oil Pump Body, Separator, and Cover (1, 11, 12, 20, FIG. 99)
1
Cracks (FPI)
None
Replace pump.
2
Wear of gear pockets
Max. of 0.005 in. (0.13
Replace pump.
mm)
3
Gear end clearance
0.0005-0.0015in.
Select gears or lap-
(0.013-0.038 mm)
parts.
(Refer to
para 120 C. (5) for
details) or replace
pump.
Oil Pump Gears
4
Cracks in radii root cor-
None
Replace pump.
ners of spline teeth or
in line or parallel in
close proximity on in-
volute of a gear tooth
side (visual with magni-
fication)
5
Nonmetallic inclusion on
Light scattered inclusions
Replace pump.
small gears and gear
parallel to material flow
shafts
lines
Open inclusion on shaft
Replace pump.
3/8 in. (10 mm) max. length
and not extending into a ra-
dius hole or spline root
6
Nicks and dents
Max. of 0.010 in.(0.25 mm)
Max. of 0.060 in.
Remove sharp
length, width or dia and
(1.52 mm) length,
edges by stoning.
without sharp corners
width or dia after
sharp corners are
removed
7
Tooth damage which in-
None
Replace pump.
volves metal displace-
ment to a degree where
subsurface damage is
detected by magnetic
inspection
Page 247
TABLE 18
Oil Pump Inspection Limits - continued
Item Condition
Serviceable Limit
Repairable Limit
Disposition
Oil Pump Gears (cont)
8
Scuffing
Scuffing when accompa-
Scuffing evidenced
Remove sharp
nied by wear-off of metal
by pickup
edges by stoning.
pick-up if gear assembly is
still matched with mating
gears
Oil Pump and Gas Producer Tachometer Spur Gearshaft (9, FIG. 99)
9
Seal journal wear
Max. of 0.0015 in. (0.038
Replace pump.
mm) radial wear on dia
10
Spline wear
Max. of 0.002 in. (0.05
Replace pump.
mm) wear measured from
adjacent unworn area
11
Scoring, grooves, nicks,
Evenly polished surface in
Replace pump.
gouges, scuffing or min-
seal contact without lead or
ute flats on shaft sealing
axial marking
journal surfaces
Pump Bushings and Dowel Pins
12
Loose or bent dowel
None
Replace pump.
pins
13
Wear on ID of pump
Replace pump.
bushings
Gearshafts
14
Gearshafts loose in
No looseness allowed
Replace or secure
scavenge oil pump
loose gearshafts
cover
with Loctite 290 (Re-
fer to para 120 C.
(4) for details
(b) Place cover assembly on the scavenge body assembly. Install oil pump drive gear and oil
pump idler gear. Lubricate and install two O-rings in the separator body. Place separator
body on the scavenge body assembly.
(c) Install oil seal plug in oil pump and gas producer tachometer spur gearshaft if it has been
removed. Install oil pump idler spur gear and oil pump and gas producer tachometer spur
gearshaft on the separator body.
(d) Lubricate and install O-ring in pressure oil pump body. Place pressure oil pump body on
scavenge body assembly. Install two screws; Torque to 18-22 lb in. (2.0-2.5 N.m).
NOTE: The pump must turn freely by hand after assembly.
Page 248
124. Gearbox Assembly
A.
Assemble the lube oil filter housing as follows (Ref. FIG. 97, Sheet 1 of 2.)
CAUTION: INSPECT THE RETAINING RING BEFORE INSTALLATION TO BE SURE IT HAS
NO DEFECTS AND AFTER INSTALLATION TO BE SURE IT IS PROPERLY
SEATED.
(1) Install the poppet, spring, lubricated O-ring, and guide in the filter housing. Retain with an
internal retaining ring. Use 6798807 compressor to aid in installation of retaining ring.
(2) Lubricate and install the O-ring on the pressure regulator guide. Insert poppet, spring, and
guide into the filter housing. Make an approximate adjustment of the regulator by bottoming
the adjusting screw and backing out 5-1/2 turns.
B.
Test the lube oil filter housing as follows:
(1) Plug the standpipe and install the cap on the filter housing.
(a) Connect a supply of calibration fluid at 24-29°C (75-85°F) or engine oil at 27-38°C
(80-100°F) to the filter housing inlet port.
(b) Slowly apply increasing pressure until the bypass valve opens. Pressure must be 80-130
psig (552-896 kPa).
(c) Decrease pressure to 30 psig (207 kPa). Leakage through the bypass valve must not
exceed 63 cc per minute.
(d) Connect the fluid supply to the outlet port and plug the inlet port.
(e) Adjust the fluid supply to obtain a flow of 720 pph (327 kg/hr) across the filter.
(f)
Adjust the guide assembly until 130 + 5 psig (862-931 kPa) is obtained with 720 pph (327
kg/hr) flow.
(g) Decrease flow to 15 pph (6.8 kg/hr). Pressure must not be less than 125 psig (862 kPa).
If pressure is not within limits, repeat steps (e) and (f), adjusting the guide assembly for a
higher pressure within the 130 + 5 psig (862-931 kPa) range. If pressure is less than 125
psig (862 kPa) at 15 pph (6.8 kg/hr) replace the pressure regulating poppet valve and
repeat the entire test.
(h) Remove the cap and remove the plug from the stand pipe. Remove the plug from the
inlet port.
(i)
Lubricate the O-rings then install the filter assembly with new O-ring and cap with O-ring
in the filter housing. Secure the cap with two nuts and washers. Torque nuts to 35-40 lb
in. (3.9-4.5 N.m).
C.
Assemble the gearbox housing as follows (Refer to FIG. 93):
(1) Install gearbox housing seals as necessary at the following locations using 6796941 seal
installation kit with details -16 or -19.
(Ref. FIG. 100 and 101) Apply grease to the seal lip to
aid in installation.
(a) Power turbine tachometer generator pad (use detail -16).
(b) Gas producer tachometer generator pad (use detail -16).
(2) Lubricate and install the two O-rings on the oil transfer tube and the two O-rings on the
connector. Install the transfer tube and connector in the gearbox housing. (Ref. FIG. 102)
Page 249
Power and Acessories Gearbox Housing Oil Seal Location
FIG. 100
Page 250
Typical Seal Installation
FIG. 101
Oil Transfer Tubes in Gearbox Housing
FIG. 102
Page 251
(3) Lubricate O-ring on oil scavenge pickup tube and insert tube in the pump. (Ref. FIG. 97,
Sheet 1 of 2.)
(4) Lubricate and install the O-ring on the underside of the lube pump. (Ref. FIG. 97, Sheet 2 of
2.) Position the pump mounting gasket and install the pump in the gearbox housing using
6796941 seal guide with detail -13. (Ref. FIG. 103) Install the filter inlet and filter bypass
tubes with lubricated O-rings. Insert eight pump attaching screws and six washers. Washers
are used at positions 1, 3, 4, 5, 6, and 7 counting clockwise with 1 at the point nearest the filter
housing. The five 10-32 X 2 in. screws go at positions 1, 2, 3, 7, and 8; the two 10-32 X
2.750 in. screws go at positions 4 and 6; the 10-32 X 2.375 in. screw goes at position 5. Do
not tighten screws at positions 2 and 8 at this time, tighten others finger tight.
(5) Lubricate and install the two O-rings on the check valve; install the valve in the gearbox
housing. (Ref. FIG. 104)
(6) Position the gasket and install the filter housing assembly in the gearbox housing. (Ref. FIG.
97, Sheet 1 of 2.) Mate the filter inlet and filter bypass transfer tubes and check valve to the
filter housing during the assembly. (Ref. FIG. 104) Retain the housing with eight nuts and
washers. Torque nuts to 35-40 lb in. (3.9-4.5 N.m). Align the two tubes then Torque the
pump attaching screws to 35-40 lb in. (3.9-4.5 N.m) and secure with lockwire. Torque the
scavenge pickup tube retaining screw to 20-25 lb in. (2.3-2.8 N.m).
Lube Oil Pump and Seal Guide
FIG. 103
Page 252
Lube Oil Pump and Filter Housing Removal or Installation
FIG. 104
(7)
Lubricate and install two O-rings on each of the three oil scavenge transfer tubes; install the
short tube in the gearbox housing.
(8)
Lubricate and install two O-rings on the oil delivery tube, one O-ring on the screen, and one
O-ring on the oil pressure tube. Install the oil pressure tube (nozzle) and the oil delivery tube
with screen in the gearbox housing. Retain each with a screw; Torque screws to 22-26 lb in.
(2.5-2.9 N.m) and secure with lockwire.
(9)
Perform a static leak check of the oil filter housing and lube oil pump assembly.
(a) Equipment. A six foot length of one-inch ID copper tubing having a length of hose with a
shutoff valve near the outlet end; a four foot head of oil in the stand-pipe; and a fitting for
connecting the hose to the oil-in port of the gearbox.
(b) Attach the fitting to the gearbox and the standpipe hose to the fitting. Keep the hose
coupling loose until the system can be bled. Open the shutoff valve and bleed the air
from the system, then tighten the hose coupling nut.
(c) Place the gearbox housing in a vertical position with the oil pump at the top.
(d) Visually check the partial assembly for oil leakage over a period of ten minutes.
NOTE: Leakage will be evident if a problem exists. Slight moistness or seepage should not
be interpreted as leakage.
(e) Correct the condition causing leakage before proceeding with the assembly of the
gearbox.
(10) Install the helical power takeoff bearing outer race and rollers in the gearbox housing. DO
NOT apply petrolatum or grease to the rollers. Lubricate using engine oil only.
Page 253
(11)
Install the idler gear support shaft in the gearbox housing using 6795614 pusher and puller.
(Ref. FIG. 94)
(12) Lubricate and install the bearing in the power train idler spur gear, retain with an internal
retaining ring. Install the gear and bearing on the shaft. Apply Locktite No. 242 lightly to the
bolt threads; then retain the gear assembly on the shaft with a bolt, a keywasher and a keyway
bearing retaining washer. Torque bolt to 35-40 lb in. (3.9-4.5 N.m) and bend locktab.
(13) Install the bearing inner race on the torquemeter support shaft. Install with the thrust flange
toward the torquemeter piston using 6796930 plate, location D, and 6796947 drift. (Ref. FIG.
105) Apply a thin coat of petrolatum to the bearing and assemble the bearing outer race and
rollers on the shaft. Install the bearing end plate and washer on the shaft. Lubricate and
install the expander ring and piston ring in the torquemeter support shaft piston ring groove.
The gap of the ring shall be 180° removed from the gap of the expander ring.
(14) Lubricate and install the ball bearing on the torquemeter piston using 6796930 plate, location J
and 6796947 drift. Install with the wide portion of the outer race away from the torquemeter
piston. Install the piston on the torquemeter support shaft. Lubricate the O-ring and place it
on the shaft.
(15) Install the torquemeter support shaft in the gearbox housing. (Ref. FIG. 93) Install 6795974
aligning fixture.
(Ref. FIG. 96) Install the internal flared washer and lubricated O-ring on the
shaft. Torque the nut using 6795597 wrench to 275-300 lb in. (31-34 N.m), and secure with
lockwire.
(Ref. FIG. 95)
Torquemeter Support Shaft Bearing Installation
FIG. 105
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(16) Lubricate and install the bearings on the tachometer and governor power train spur gearshaft
using 6796930 plate, locations C and G and 6796946 drift.
(17) Apply lubricant lightly to the splines then install the tachometer and governor spur gearshaft in
the gearbox housing using 6796941 seal guide with detail -13.
(18) Lubricate and install the bearings on the fuel control and oil pump spur gearshaft using
6796930 plate, location H and 6796946 drift. The small ball bearing that was pulled by the
outer race must be replaced with a new bearing at this step if there is any apparent indication
of raceway brinelling. Install the gearshaft in the oil pump bearing cage.
(19) Apply lubricant lightly to the splines then install the fuel control and oil pump flex shaft coupling
on the oil pump drive shaft. (Ref. FIG. 97, Sheet 2 of 2.)
D.
Assemble the gearbox cover as follows (Refer to FIG. 83)
(1) Install gearbox cover seals as necessary at the following locations using 6796941 seal
installation kit with details -16, -17, -19, and -20.
(Ref. FIG. 101 and 106) Apply grease to
the seal lip to aid in installation.
(a) Power turbine governor pad (use detail -17).
(b) Power takeoff pad (use detail -19).
(c) Gas producer fuel control pad (use detail -17).
(d) Fuel pump pad (use detail -17).
(e) Accessory drive pad (use detail -17).
(f)
Starter generator pad (use detail -18).
(g) Gas producer idler spur gearshaft (internal installation held by a retaining ring) (use detail
-20).
Power and Accessories Gearbox Cover
FIG. 106
Page 255
(2)
Install the three idler gear support shafts in the gearbox cover using 6795614 pusher and
puller.
(Ref. FIG. 92) Lubricate and install the bearings in the three gas producer gear train
idler spur gears, retain with internal retaining rings.
(Ref. FIG. 91) Install two idler spur gears
and bearings on the idler shafts. Retain the two gear assemblies with bearing retaining
washers, key washers, and bolts which have been lightly coated with Locktite No. 242.
(3)
Lubricate and install the ball bearings on the gas producer gear train idler spur gearshaft using
6796946 drift and 6796930 plate, locations F and H.
(4)
Install the third idler spur gear, bearing retaining washer, keywasher and bolt at the same time
the gas producer gear train idler spur gearshaft is installed. Coat the bolt lightly with Loctite
No. 242 before installation. Torque the three bolts that retain the idler gears to 35-40 lb in.
(3.9-4.5 N@m) and bend locktabs of the keywashers.
(5)
Install the internal retaining ring then lubricate and install the two ball bearings, one at a time,
and the bearing sleeve spacer on the accessory drive spur gearshaft using 6796949 drift and
6796930 plate, location C. A 0.000-0.0007T fit between the inner race ID and the shaft OD
must be maintained. Install the bearing retainer and secure it with an external retaining ring.
Apply lubricant to the splines of the gearshaft and using 6796941 seal guide with detail -14,
install the gearshaft in the gearbox cover. Secure with an internal retaining ring using 6796966
pliers.
(6)
Install the fuel pump drive spur gearshaft in the same manner that the accessory drive spur
gearshaft was installed (step (5).
(7)
Lubricate O-ring and install it on the starter-generator spur gearshaft. Assemble the
starter-generator spur gearshaft in the same manner that the accessory drive spur gearshaft
was installed (step (5).
(8)
Lubricate two O-rings and install with oil transfer tube in the gearbox cover.
(9)
Lubricate O-ring and install it on the fuel control spur gearshaft. Assemble the fuel control
spur gearshaft in the same manner that the accessory drive spur gearshaft was installed (step
(5).
(Ref. FIG. 83, Sheet 1 of 2.)
CAUTION: FAILURE TO INSTALL THE INTERNAL RETAINING RING IN THE HELICAL
POWER TRAIN DRIVE GEAR (RETAINING RING CONFIGURATION) CAN ALLOW
DISENGAGEMENT OF THE TURBINE SHAFT-TO-PINION GEAR COUPLING
CAUSING POWER TURBINE OVERSPEED.
(10) If the helical power train drive gear incorporates an internal retaining ring groove, install the
internal retaining ring. Drive gears which have an integrally-cast oil dam in place of a retaining
ring groove do not require a retaining ring. Install the two ball bearings on the drive gear using
6796948 drift and 6796930 plate, location A. The bearings shall be selected to obtain an
internal clearance of not less than 0.0003 in. (0.0076 mm) after assembly on the gear. Check
clearance using 6872165 gage. Chill the gear, -60°C (-76°F) max, and heat the bearings,
121°C (250°F) max, to aid the installation. When bearings have cooled, lubricate bearings and
install the gear in the gearbox cover, secure in place with the internal retaining ring.
(11) Lubricate and install the ball bearing on the helical power takeoff gearshaft using 6796948 drift
and 6796930 plate, location A. (Ref. FIG. 107) Uniformly heat to 177-204°C (350-400°F),
and install the roller bearing inner race on the gearshaft using 6796948 drift and 6796930
plate, location B. Hold the heated bearing race in position against the gear shoulder until heat
distribution has normalized. Apply lubricant to the splines of the gearshaft and using 6796941
seal guide with detail -15, install the gearshaft in the gearbox cover.
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Power Takeoff Gearshaft Bearing Installation
FIG. 107
(12) Lubricate and install the O-ring in the groove at the torquemeter shaft opening of the gearbox
cover. Lubricate and position the thrust washer and bearing end plate in the gearbox cover.
Use petrolatum to retain the bearing outer race and rollers of the torquemeter bearing in the
torquemeter gearshaft. Place the gearshaft in position in the cover, meshing the gear teeth
with the teeth of the helical power train drive gear and the helical power takeoff gearshaft.
Lubricate and install the roller bearing inner race on the torquemeter shaft support using
6796930 plate, location E and 6796947 drift. Install the headed pin in the shaft support. Install
the shaft support in the cover through the gear using 6795969 holder. (Ref. FIG. 108) Secure
the support with a cup washer and spanner nut lightly coated with antiseize compound.
Torque spanner nut to 390-400 lb in. (44-45 N.m) using 6795597 wrench. (Ref. FIG. 95)
Crimp cup washer securely into locknut slot.
(13) Apply anti-seize compound to the oil nozzle mounting studs; install oil nozzle with lubricated
packing. Secure with two nuts. Torque nuts to 35-40 lb in. (3.9-4.5 N.m).
(14) Lubricate packing and install with magnetic plug in the bottom of the gearbox cover. Torque
plug to 60-80 lb in. (6.8-9.0 N.m) and secure with lockwire.
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