Operation & Maintenance Manual──LG956L Wheel Loader
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brake valve 6 into the air chamber of the air booster pump. The compressed air pushes the piston of
the booster pump to change the oil pressure (oil pressure is about 14MPa). Brake fluid pushes the
piston of the caliper disk brake and makes the friction disk contact the brake plate to achieve the
purpose of slowing and braking.
Release the brake pedal, and the compressed air of the booster pump drains from the brake valve to
the atmosphere and the brake is released.
When assemble the select switch for cutting off power, if switch valve handle locates in the ‘power
cutting off’ position, the power outputted by transmission box is cut off while braking to utilize better
braking effective and higher production; when the switch valve handle locates in the ‘power
connecting’ position, the power outputted by transmission box is not cut off while braking.
3.2 Driving Brake System (Double Brake Pedals)
As shown in Figure 5-5, this system is the double brake pedals, air pushing oil four wheels caliper
disk brake system using four brake calipers for front and back to increase the safety of whole vehicle.
When the left brake pedal is stepped on during driving, the compressed air in air tank 4 flows through
air brake valve 3 and shuttle valve 2 into the air chamber of the air booster pump 1. The compressed
air pushes the piston of the booster pump to change the oil pressure (the max oil pressure is about
14MPa). Brake fluid pushes the piston of the caliper disk brake and makes the friction disk contact
the brake plate to achieve the purpose of slowing and braking. At the same time output the signal of
air pressure and cut off the power of transmission box.
When the right brake pedal is stepped on during driving, the brake principle is the same as left brake
pedal, but the power of transmission box is not cut off.
Release the brake pedal, and the compressed air of the booster pump drains from the brake valve to
the atmosphere and the brake is released.
3.3 Emergency and Parking Brake System (Manual Air Control Caliper
Cisk)
As shown in Figure 5-4, this system employs the spring air chamber caliper disk type brake system.
During driving, press the operating button of brake electromagnetic valve, and then the compress air
in the air tank 4 through the brake electromagnetic valve 7 to the parking brake air chamber 8 to pull
the plug away and release the brake; When stopping, press the operating button of brake
electromagnetic valve 7, the compress air in the parking brake air chamber 8 through the air draining
port of brake electromagnetic valve to aerospace. Then the brake is pulled up under the spring to
arrive to brake. The parking brake indicator lamp controlled by output air pressure is lightened to
remind the operator that the whole vehicle is in the braking state.
When the system air pressure is lower than 0.28Mpa, the operating button of manual control brake