PLATE 1395256 - Caterpillar

BRAKE CONTROL VALVE-PEDAL RELEASED
1-Lever. 2-Rotary actuator housing. 3-Shims. 4-Springs. 5-Return oil passage to oil supply tank. 6-High pressure oil passage from accumulator. 7-Spring. 8-Piston. 9-Brake pedal. 10-Plunger. 11-Valve body. 12-Valve spool. 13-Passage to wheel brakes. 14-Passage. 15-Orifice check valve.When brake pedal (9) is released, the force of springs (4) on valve spool (12) is released. The combined force of pressure oil on piston (8) and spring (7) moves the valve spool toward springs (4). This movement opens return oil passage (5) to passage (13) from the wheel brakes. Retracting springs (located in the wheel brakes) force oil from the brakes through passage (13), around the valve spool into return oil passage (5) releasing the brakes. High pressure oil passage (6) from the accumulator remains blocked.The maximum oil pressure to the brakes is adjusted by adding or removing shims (3).Wheel Brakes
Pressure oil from the brake control valve enters chamber (8) in housing (5) and forces piston (7) to compress damper assemblies (1), discs (2) and plates (4). Since discs (2) are splined to hub (3) and plates (4) are splined to housing (5), the friction created between the discs and plates as they are compressed, retards or stops the rotation of the hub and wheel spindle.Releasing the brake control valve allows the pressure oil behind piston (7) to flow back to the hydraulic oil supply tank through the brake control valve.Springs (6) pull piston (7) away from the brake plates and discs, relieving the friction and releasing the brake.The brakes are lubricated and cooled by oil in the tandem drive housings.
BRAKE CROSS SECTION-BRAKES RELEASED
1-Damper assemblies (two). 2-Discs (nine). 3-Hub. 4-Plates (approximately eight). 5-Housing. 6-Springs (six). 7-Piston. 8-Oil chamber. 9-Wheel spindle.Brake, Implement And Steering Relief Valves
RELIEF VALVES-SCHEMATIC
1-Shims, brake and implement. 2-Pilot valve. 3-Dump valve. 4-Implement circuit return port. 5-Steering circuit return port. 6-Dump valve. 7-Pilot valve. 8-Shims, steering. 9-Test plug, brake and implement. 10-Test plug, steering. 11-Steering outlet port. 12-Brake and implement port. 13-Return port to tank. 14-Steering inlet port.The brake and implement circuits relief valve and the steering circuit relief valve are contained in one housing. The operation of the relief valves is the same.System pressure is sensed on the dump valve and pilot valve. When the oil pressure approaches the relief valve setting, the pilot valve unseats, allowing the oil in the chamber between the pilot valve and dump valve to return to the tank, creating a pressure drop in this chamber. As the pressure acting on the dump valve increases to the relief valve setting, the dump valve moves against the force of its spring. Full pump flow is then directed back to the tank.Shims (1) control the brake and implement maximum pressure setting. Shims (8) control the steering maximum pressure setting. Adding shims will increase the pressure settings.Emergency And Parking Brake
EMERGENCY AND PARKING BRAKE SCHEMATIC
1-Brake control valve. 2-Line from pump. 3-Parking brake control valve. 4-Range transmission. 5-Line to wheel brakes. 6-Junction block. 7-Emergency and parking brake. Note: The brake control valve (1) is in the applied