BUSHING 2857226 - Caterpillar

Illustration 1 g00455125
Components of the Service Brakes (1) Guides. (2) Springs. (3) Chamber. (4) Brake anchor. (5) Plates. (6) Discs. (7) Wheel spindle. (8) Wheel. (9) Piston. (10) Chamber.The service brakes are positioned at all four of the final drives. The service brakes are activated by pressure oil. The heat from the friction of the brakes is removed by a separate cooling oil circuit.Brake anchor (4) is fastened to each wheel spindle (7). The wheel spindle and the brake anchor do not rotate as the machine moves.The splines on the outside circumference of plates (5) mesh with the splines in brake anchor (4). The splines prevent the plates from rotating.The splines on the outside circumference of wheel (8) mesh with the splines on the inside circumference of discs (6). This allows wheel (8) and discs (6) to rotate together as the machine moves.The discs have grooves which allow cooling oil that is in chamber (3) to pass between the plates and the discs. If the depth of the grooves in the discs is adequate, the cooling oil constantly flows between the discs and the plates. This happens even when the service brakes are applied.
Illustration 2 g00455163
View of the Pedals (11) Left pedal. (12) Service brake pedal.When either service brake pedal (12) or left pedal (11) is pushed, pressure oil flows from the service brake valve into chamber (10). Oil in chamber (10) pushes piston (9) against plates (5) and discs (6). This causes friction between plates (5) and discs (6). The plates are held stationary by anchor (4) and the discs turn with the rotation of the wheels. This friction causes the wheels to turn at a slower rate or to stop. The amount of brake application is caused by the position of the brake pedal.When the brake pedal is released, the oil from chamber (10) flows through the service brake valve and to the hydraulic oil tank. Springs (2) move piston (7) away from plates (5) and discs (4). The movement of the oil between the plates and discs helps in separation, as piston (7) moves to the released position. This allows the wheels to rotate.Note: If the service brakes become inoperative then the parking brake should be engaged. In this application, the parking brake system functions as the secondary brake system. If the parking brake is used to stop the machine, damage to the parking brake could occur. The parking brake should be used to stop the machine when the service brakes are not functioning. The parking brake should be serviced after an emergency stop.