Operation & Maintenance Manual
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LG918 Wheel Loader
104
3.1 Driving Brake System (Single Brake Pedal)
As shown in Figure 5-4, this system is the single line, air pushing oil four wheels caliper disk brake
system. When the brake pedal is stepped on during driving, the compressed air in air tank 3 flows
through air brake 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 (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.
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 two 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 Parking Brake System
This system employs the manual pliers-disc braking system.
Pull the control lever when you want to brake. Pull the brake by the soft past of the shaft to achieve
braking. At the same time, send an electric signal to turn on the parking brake indicator, by which to
alarm the operator that the vehicle is in the braking condition.
4 ELECTRIC SYSTEM
The electric system is composed of a storage battery, starting motor, charge generator, appliance,
switch, lamps, air conditioning circuit and other electric instruments.
The system of this machine employs D.C. 24V voltage, negative electrode and single wire lines. The
relation of each electric instrument and their working theories refer to the diagram sketch of the
electric system as is shown in figure 5-6, 5-7 and 5-8.
