 | |
| Illustration 1 | g00482736 |
Brake Hydraulic System (1) Left brake bleeder screw (2) Line to the left rear disc brakes (3) Line to the right rear disc brakes (4) Right brake bleeder screw (5) Drain line to the rear housing of the transmission (6) Line to the right and left rear disc brakes (7) Brake master cylinder (8) Master cylinder reservoir (9) Inlet line from the transmission control valve (10) Brake boost (11) Transmission hydraulic control | |
The rear service brake assemblies are located in the center housing. The machine uses oil cooled multi-disc brakes. One multiple disc brake is located on each side of the machine. Both brakes are actuated by the service brake pedal. The service brakes are lubricated by oil from the differential steering system.
The parking brake is a dry disc brake. The parking brake acts on the input shaft for the differential steer unit. In certain conditions, the parking brake can be used as a secondary brake system.
The service brake system consists of the following components: brake master cylinder (7), master cylinder reservoir (8), brake boost (10), transmission hydraulic control (11), service brake pedal (not shown) and rear multiple disc brakes (not shown).
The service brake system has two different hydraulic circuits. The first hydraulic circuit is used in order to operate the disc brakes. The second circuit provides brake boost to the master cylinder. This reduces the brake pedal effort that is required by the operator.
The service brake system is equipped with two brake purging screws (1) and (4) in order to remove air from the system.
When the engine is running, the transmission charge pump which is fastened to the steering pump takes oil from the common sump.
Oil from the common sump flows through the transmission filter to transmission hydraulic control (11) .
Transmission hydraulic control (11) sends oil to brake boost (10). Return oil flows through the drain line to the center housing of the transmission (5) .
When the service brake pedal is depressed, brake boost (10) restricts the output flow. This increases the boost pressure which multiplies the force from the brake pedal linkage that is connected to master cylinder (7) .
Pressurized hydraulic oil from master cylinder (7) is sent through line (6) to a tee. The tee is located near the front of the center housing.
The pressurized oil divides at the tee before flowing through both inlet line (2) and inlet line (3). The pressurized oil is routed to the cavities behind the actuator pistons for both the left rear disc brakes and the right rear disc brakes.
The pressurized oil forces the actuator pistons to move against the following components: friction disc, separator plates and end plates.
The compressed friction discs can be slowed or prevented from moving. This causes the planetary gears to be slowed or prevented from moving.
When the brake pedal is released, pressure that is behind the actuator pistons is drained through the brake valve. The actuator piston retracts. This releases the compressed friction discs and separator plates.
If the brake pedal is depressed 50.8 mm (2 inch), the pressure of the brake application is approximately 1720 kPa (250 psi).
Master cylinder reservoir (8) supplies makeup oil for master cylinder (7).