RIVET 4B4421 - Caterpillar

Illustration 1 g03671380
(1) Brake lights
(2) Right brake pedal
(3) Left Brake pedal
(4) Rear brake accumulator
(5) Front brake accumulator
(6) Rear service brakes
(7) Service brake valve
(8) Front service brakes
(9) Shuttle valve
(10) Accumulator pressure sensor
(11) Pressure reducing valve
(12) Sequence valve
(13) Relief valve
(14) Parking brake spool
(15) Parking brake solenoid
(16) To parking brake
(17) Brake oil filter
(18) Brake/pilot pump
(19) To implement/steering system
(20) Parking brake control valve The front brake accumulator and the rear brake accumulator are continuously charged when the engine is running. The accumulators will continue to charge until the oil pressure increases to 16000 350 kPa (2,320 50 psi), which is the brake/pilot pump cutoff pressure. At cutoff pressure, the brake/pilot pump will destroke. When the brake circuit pressure decreases to approximately 10600 kPa (1535 psi), the brake accumulator pressure sensor will send a signal to the Power Train ECM.The inverse shuttle valve maintains equal pressure between both brake accumulators. The check valve prevents the high-pressure oil in the passages to the inverse shuttle valve from flowing back to the brake/pilot pump.