- Load Haul Dump:
- R2900G (S/N: JLK865-UP)
The following additional information is for the parking brake control valve section of the Service Manual. The new information is effective with JLK865-UP.
Brake Control Valve (Parking)
S/N: JLK865-UP
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| Illustration 1 | g01138165 |
The parking brake control valve is located on the left side of the rear frame.
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| Illustration 2 | g01515593 |
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 switch (8) 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).
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| Illustration 3 | g01515614 |
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 hydraulic tank (7) Parking brake oil pressure switch (8) Port to parking brakes (9) Spool | |
When the engine is running and the parking brake switch is in the ON position, no power is supplied to parking brake solenoid valves (2). Pressure oil from the pilot relief valve at port (5) is stopped by valve spools (9). 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 (8), and valve spools (9) and port (6) .
When the parking brake switch is moved to the OFF position, power is supplied to parking brake solenoid valves (2). Parking brake solenoid valves (2) energize and move spools (9). Pressure oil from the pilot relief valve at port (5) flows through valve spools (9) and port (8) to the parking brakes. Oil pressure disengages the parking brakes and allows the machine to move.