YOKE AS 2V5894 - Caterpillar

Illustration 1 g02936996The parking brake control valve is located on the left side of the rear frame.
Illustration 2 g03178605
Parking brake control valve
(1) Parking brake solenoid valve for the remote control system
(2) Parking brake solenoid valves
(3) Solenoid valve for implement and steering lockout
(4) Pressure tap for the parking brake circuit
(5) Port from the pilot relief valve
(6) Port to hydraulic tank
(7) Parking brake oil pressure sensor
(8) Parking brake oil pressure switch
(9) Port to parking brakes The parking brake control valve has two parking brake solenoid valves (2) controlled by a parking brake switch in the operator station. The remote control system when fitted also controls the operation of parking brake solenoid valve (1) and parking brake solenoid valves (2). The operation of parking brake solenoid valve (1) is identical to parking brake solenoid valves (2).
Illustration 3 g03178616
Schematic for the parking brake control valve
(1) Parking brake solenoid valve for the remote control system
(2) Parking brake solenoid valves
(3) Solenoid valve for implement and steering lockout
(4) Pressure tap for the parking brake circuit
(5) Port from the pilot relief valve
(6) Port to parking brakes
(7) Parking brake oil pressure sensor
(8) Parking brake oil pressure switch
(9) Port to hydraulic tank
(10) Valve spool When the engine is running, and the parking brake switch is in the ON position, no power is supplied to the coil of parking brake solenoid valve (1) (if equipped) and the coil of parking brake solenoid valves (2). Pressure oil from the pilot relief valve at port (5) is stopped by valve spools (10). The parking brakes are engaged by the force of the parking brake springs. Oil from the parking brakes is free to return to the hydraulic tank through port (9), valve spools (10), and port (6).When the parking brake switch is moved to the OFF position, power is supplied to the coil of parking brake solenoid valve (1) (if equipped) and the coil of parking brake solenoid valves (2). When parking brake solenoid valve (1) (if equipped), and parking brake solenoid valves (2) are energized, valve spools (10) move. Pressure oil from the pilot relief valve at port (5) flows through valve spools (10) and port (6) to the parking brakes. Oil pressure disengages the parking brakes and allows the machine to move.