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| Illustration 1 | g00366452 |
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. The machine will move if the control lever is in either forward or reverse speed, and the parking brake is not engaged. Machines that are equipped with a creeper will not move if the creeper speed control is pulled to the back of the machine.
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| Illustration 2 | g00366532 |
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) Spring. (11) Piston seals. (12) 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 front axle and 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 (12) 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 (12) , 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.
Service Brake Oil Pressure Switch
The service brake oil pressure switch (13) is located on the left side of the machine under the operator's platform. The switch is attached to the accumulator manifold.
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| Illustration 3 | g00411240 |
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| Illustration 4 | g00370372 |
Location of the Light for the Service Brake Oil Pressure Switch (14) Light for the service brake oil pressure switch. | |
The brake oil pressure switch (13) is located on the left side of the machine under the cab. Brake oil pressure indicator (14) is located on the left control panel in the operator's cab. When the oil pressure in the accumulator charging valve drops below the minimum operating pressure, the brake oil pressure indicator (14) turns on. Refer to Operation and Maintenance Manual for the 914G Wheel Loader, SEBU6868 or to Operation and Maintenance Manual for the IT14G Integrated Toolcarrier, SEBU6869 .