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| Illustration 1 | g00486901 |
Service Brake Pedal (Arrows) | |
Depress one of the service brake pedals in order to apply the service brakes for normal braking. Releasing the pedal will release the service brakes. If the parking brake is not engaged, the machine will move when the control lever is in either FORWARD or REVERSE position and the speed select switch is in the FAST position. Machines that are equipped with a creeper will not move if the creeper speed control is toward the back of the machine.
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| Illustration 2 | g00367598 |
Components of the Service Brake (1) Planetary carrier. (2) Axle. (3) Ring gear. (4) Plate. (5) Friction disc. (6) Passage. (7) Piston. (8) Planetary gear. (9) Pin (three). (10) Piston seals. (11) Sun gear. | |
The service brake consists of the plate (4) , the friction disc (5) , the piston (7) , and the pins (9) . The service brakes are located in the axle housing assemblies. On standard machines with (PIN: 7ZM1-5998ZM1-499), only the front axle is equipped with service brakes. The high speed machine has service brakes in the front axle and in the rear axle. The service brakes do not require any adjustment.
The plate (4) and the piston (7) are held stationary by the three pins (9) . The three pins (9) are fastened to the differential housing and the axle housing. The piston (7) and the plate (4) are able to slide on the three pins, but the piston (7) and the plate (4) cannot rotate.
The friction disc (5) has splines on the inside diameter that fits onto the splines of the sun gear (11) . The friction disc (5) rotates at the same speed as the sun gear (11) . Oil flows in the grooves that are on the friction disc (5) in order to cool the service brakes. The cooling oil flows between the friction disc (5) and the plate (4) and between the friction disc (5) and the piston (7) . The cooling oil flows in the grooves, while the brakes are applied.
The planetary carrier (1) is fastened with splines to the axle (2) . The planetary carrier (1) rotates at the same speed as the axle. The three planetary gears (8) rotate between the sun gear (11) and the stationary ring gear (3) .
When one or both of the brake pedals is pushed, the brake oil from the master cylinder flows through the passage (6) into the differential housing. The force of the oil behind the piston (7) moves the piston (7) against the plate (4) . This causes friction between the disc (5) , the piston (7) , and the plate (4) . The friction causes the rotation of the sun gear (11) , the planetary carrier (1) , the axle (2) , and the wheel to decrease. The heat that is created is dissipated by the oil in the axle housing.
When the brake pedal is released, the oil behind the piston (7) is open to the reservoir and the pressure decreases. The oil pressure behind the piston (7) decreases and the brake is released.
Brake Oil Indicator Light
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| Illustration 3 | g00486902 |
Location of the Brake Oil Indicator Light (13) Brake oil indicator light. | |
The brake oil indicator light (13) turns on when the level of the brake oil is low. If this light turns on during normal machine operation, stop the machine immediately. Lower the bucket or the implement to the ground. Engage the parking brake and stop the engine.
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| Illustration 4 | g00370373 |
Location of the Reservoir for the Brake Oil (14) Reservoir for the brake oil. | |
If the brake oil indicator light turns on, check for the correct fluid level in the reservoir for the brake oil.
If the fluid level in the reservoir is low, refer to Operation and Maintenance Manual for the 914G Wheel Loader, SEBU6868 or refer to Operation and Maintenance Manual for the IT14G Integrated Toolcarrier, SEBU6869 .