SYSTEM/Hydraulic System Brake Pedal Front Brake Service Brake Service Brake Accumulators Brake Valve Rear Brake Check Valves Relief Valve Priority Valve Spring Parking Brake Solenoid Valve Parking Brake Pressure Sensor Parking Brake Release Pilot Accumulator No Signal for Parking Brake Release Charging Block Brake T4GC-02-02-003 Pilot Pump NOTE: Illustration shows oil flow when the relief valve and the priority valve are open in response to pressure increase in the service brake circuit, and also oil flow when the parking brake is working with the unexcitement of the parking brake solenoid valve. T2-3-29