 | |
| Illustration 1 | g01394456 |
Hydraulic schematic for the steering and braking system (1) Left steering cylinder (2) Right steering cylinder (3) Brake release cylinder (4) Front wheel brakes (5) Steering control valve (6) Steering release diverter valve (7) Pressure tap for the brake release system (8) Line relief and make-up valve (9) Line relief and make-up valve (10) Shuttle valve (11) Spool (12) Check valve (13) Brake release sequence valve (14) Connection for recovery hook type brake release system (15) Shuttle valve (16) Steering relief valve (17) Parking brake oil pressure switch - electronic transmission control (18) Parking brake oil pressure switch - remote control light (19) Check valve (20) Steering system pressure tap (21) Steering pilot control valve (22) Implement and steering neutralizer valve (23) Pressure tap for the parking brake and the pilot system (24) Check valve (25) Service brake pedal (26) Service brake and transmission neutralizer pedal (27) Secondary steering diverter valve (if equipped) (28) Hydraulic oil cooler (29) Rear brake accumulator (30) Front brake accumulator (31) Primary steering flow switch (if equipped) (32) Left neutralizer valve (33) Right neutralizer valve (34) Residual brake oil pressure switch (35) Pressure tap for the steering pilot system (36) Parking brake control valve (37) Residual brake oil pressure switch (38) Rear wheel brakes (39) Service brake control valve (40) Secondary steering pump (if equipped) (41) Steering pilot pressure reducing valve (42) Line from the implement lift circuit (43) Selector and pressure control valve (44) Brake accumulator oil pressure switch - alert indicator (45) Brake accumulator oil pressure switch - brake application (46) Hydraulic tank (47) Pilot oil pressure reducing valve (48) Breaker relief valve (49) Portable hydraulic pump quick connect coupler (50) Pilot and braking pump (51) Steering pump (52) Implement pump (53) Hydraulic oil filters (54) Portable hydraulic pump quick connect coupler (55) Check valve (56) Brake accumulator charging valve (57) Pressure tap for brake accumulator charging system | |
Recovery Bar
 |
If the disabled machine is in a stope or dangerous area, the recovery machine must be operated by remote control. The brake release system must only be activated by a recovery bar securely attached to the recovery machine. The recovery bar must be securely attached to the hitch of the disabled machine prior to activating the brake release system. Failure to securely attach the recovery bar may result in the disabled machine moving. Uncontrolled movement of the disabled machine can cause serious personal injury or death. When the disabled machine has been towed to a safe place, ensure that the machine is parked on level ground and the wheels are blocked securely. Be sure that the machine can not move before performing any service work on the machine. Ensure that the disabled machine cannot move before disconnecting the recovery bar. |
 |
If the parking brake is engaged due to a machine fault and the machine must be towed, the brake release system can be used to release the machine brakes.
The brake release system is activated by a recovery bar compressing the piston in brake release cylinder (3). Brake release cylinder (3) is located in the machine towing hitch at the rear of the machine.
The brake release system consists of the following components: brake release cylinder (3), brake release sequence valve (13), check valve (12) and shuttle valve (10).
 | |
| Illustration 2 | g01395339 |
Rear view of the machine (3) Brake release cylinder | |
 | |
| Illustration 3 | g01395340 |
Left side view of the rear frame (13) Brake release sequence valve | |
 | |
| Illustration 4 | g01395341 |
Left side view of the rear frame (10) Shuttle valve | |
When the brake release system is activated, the recovery bar compresses the piston in brake release cylinder (3) against spring pressure. The hydraulic oil in brake release cylinder (3) is forced from the cylinder and directed through shuttle valve (10) to wheel brakes (4) and (38). The oil pressure then disengages the parking brake section of the wheel brakes.
When the recovery bar is removed, the brake release system is deactivated and the piston in brake release cylinder (3) is returned by spring pressure. The hydraulic oil disengaging the parking brake is now returned to brake release cylinder (3). The parking brake will now be engaged.
Brake release sequence valve (13) ensures that the brake release system is disabled when the parking brake is disengaged.
Recovery Hook
|
If the disabled machine is in a stope or dangerous area, the recovery machine must be operated by remote control. The brake release system must only be activated by a tow line securely attached to the recovery machine. The tow line must be securely attached to the recovery hook of the disabled machine prior to activating the brake release system. Failure to securely attach the tow line may result in the disabled machine moving. Uncontrolled movement of the disabled machine can cause serious personal injury or death. When the disabled machine has been towed to a safe place, ensure that the machine is parked on level ground and the wheels are blocked securely. Be sure that the machine can not move before performing any service work on the machine. |
|
If the parking brake is engaged due to a machine fault and the machine must be towed, the brake release system can be used to release the machine parking brake.
The brake release system consists of the following components: brake release cylinder (3), brake release sequence valve (13), check valve (12) and shuttle valve (10).
 | |
| Illustration 5 | g01395349 |
Rear view of the machine (3) Brake release cylinder (58) Recovery hook | |
The brake release system is activated by an external force being applied to recovery hook (58). Recovery hook (58) is located at the rear of the machine.
 | |
| Illustration 6 | g01395350 |
Left side view of the rear frame (13) Brake release sequence valve | |
 | |
| Illustration 7 | g01395354 |
Left side view of the rear frame (10) Shuttle valve | |
When the brake release system is activated, recovery hook (58) compresses the piston in brake release cylinder (3) against spring pressure. The hydraulic oil in brake release cylinder (3) is forced from the cylinder and directed through shuttle valve (10) to the wheel brakes. The oil pressure then disengages the parking brake section of the wheel brakes.
When the external force on recovery hook (58) is removed the brake release system is deactivated, and the piston in brake release cylinder (3) is returned by spring pressure. The hydraulic oil disengaging the parking brakes is now returned to brake release cylinder (3). The parking brakes will now be engaged.
Brake release sequence valve (13) ensures that when the engine is running, the brake release system is disabled.
Steering Release
In the event of a machine fault and the machine must be towed, the optional brake release system can be used to release the machine steering.
The steering release is activated by either of two methods: A recovery bar attached to the recovery machine or by a tow line attached to the recovery hook of the disabled machine. Both methods exert an external force on the piston in the brake release cylinder.
The steering release system consists of the following components: brake release cylinder (3), steering release diverter valve (6) and brake release sequence valve (13).
 | |
| Illustration 8 | g01395356 |
(3) Brake release cylinder (typical example) | |
Brake release cylinder (3) is located on the rear of the machine.
 | |
| Illustration 9 | g01395357 |
(13) Brake release sequence valve | |
Brake release sequence valve (13) is located on the left side of the rear frame.
 | |
| Illustration 10 | g01395359 |
(6) Steering release diverter valve | |
Steering release diverter valve (6) is mounted on the steering control valve. The steering control valve is located on the rear frame behind the articulation hitch.
When the brake release system is activated, oil from brake release cylinder (3) is sent to steering release diverter valve (6). The pressure oil from brake release cylinder (3) activates steering release diverter valve (6). Steering release diverter valve (6) allows oil flow between the rod end and the head end of the steering cylinders. The machine will articulate freely whilst being towed.
Brake release sequence valve (13) ensures that the steering release system is disabled when the engine is running.