GAUGE 3D3766 - Caterpillar

Illustration 1 g00798776
(1) Brake shoes (2) Rod (3) Actuator (4) Line (5) Disc (6) Lever
Illustration 2 g01135846
(7) Chamber (8) Actuator piston (9) SpringThe parking brake is located in front of the center axle. Disc (5) is part of the drive shaft.The parking brake is engaged by spring force and the parking brake is disengaged by oil pressure.The parking brake is controlled by the parking brake control in the cab. The parking brake engages automatically when the engine is shut off.When the parking brake control is moved to the DISENGAGED position, oil flows through line (4) and into chamber (7). The oil moves actuator piston (8) against spring (9) and rod (2) moves forward. Motion of rod (2) rotates lever (6) in the counterclockwise direction which relieves the clamping force between brake shoes (1) and disc (5) .When the parking brake control is moved to the ENGAGED position, pressure is relieved from line (4) and chamber (7). This allows spring (9) to extend and the spring moves piston (8) and rod (2) in the direction of line (4). Motion of rod (2) rotates lever (6) in the clockwise direction which produces a clamping force between brake shoes (1) and disc (5). The clamping force opposes the motion of the disc.