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| Illustration 1 | g00756957 |
Parking brake control valve (1) Check valve (2) Solenoid valve | |
The parking brake control valve is located inside the right hand side of the rear frame. The parking brake control valve is in front of the center axle.
The parking brake control valve contains check valve (1) and solenoid valve (2). These parts control the parking brake.
Check valve (1) maintains pressure in the accumulator for the parking brake. When the engine is shut off, the brake system pressure falls below the accumulator charge pressure. The check valve closes and the check valve traps the accumulator pressure in the parking brake system.
The solenoid valve is used to control the oil flow to the actuator for the parking brake. When solenoid valve (2) is deactivated the actuator is open to the tank and spring force engages the parking brake. When the solenoid valve is activated, pressurized oil enters the actuator. The pressurized oil compresses the spring in the actuator which disengages the parking brake.