BODY ASSEM. 5J4732 - Caterpillar

Illustration 1 g03392164
Parking brake control valve overview
(6) Monitor display
(7) Can Datalink
(8) Power Train ECM
(9) Park brake switch (cab)
(10) Park brake pressure sensor
(11) Solenoid operated pilot valve
(12) Brake system pressure sensor
Illustration 2 g03392105
349-4389 Brake Control Valve Gp
(1) Port (C) out to parking brake
(2) Port (GP) pressure sensor port
(3) Port (P) line pressure from accumulators
(4) Port (T) line to tank
(5) Solenoid operated pilot valve The parking brake control valve is located on top of the frame below the cab. The parking brake control valve directs oil flow to the parking brake. The solenoid-operated pilot valve has access to oil from port "P" (3) for use in shifting the directional spool inside the parking brake control valve. When the parking brake switch in the cab is turned ON, the power train ECM de-energizes the parking brake solenoid operated pilot valve (5). The pilot valve drains the pilot signal pressure from the end of the spool to tank, out port " T" (3). Spring force shifts the spool, which blocks oil flow to the parking brake from port "P" (3) to port "C" (1) and allows oil in the parking brake to flow into port "C"(1) through to port "T"(4), back to tank. Spring force engages the parking brake."When the parking brake switch in the cab is turned OFF, the power train ECM energizes the parking brake solenoid operated pilot valve (5). The pilot valve sends signal pressure to the end of the spool. The spool shifts and directs oil from port "P" (3) to port "C" (1) and allows pressure to release the parking brake.The parking brake sensor on port "GP" (2), sends a signal to the power train ECM indicating parking brake pressure .