904B Wheel Loader Power Train Caterpillar

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Personal injury can result if the machine moves while checking the service brakes. If the machine begins to move during the check, reduce the engine speed immediately and engage the parking brake.

This following test will determine if the service brakes are functional. Before any tests are performed, visually inspect the complete braking system for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection". Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".

Test for the Service Brakes

1. Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel.

2. Lower the work tool to the ground. Stop the engine.

3. Engage the parking brake.

4. Place chocks in front of the wheels and behind the wheels.

5. Connect the steering frame lock.

6. Remove the chocks.

7. Fasten the seat belt. Start the engine. Raise the work tool slightly.

8. Apply the service brake.

9. Disengage the parking brake.

10. Move the direction control switch to the FORWARD position.

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NOTICE
Driving through the brake for more than 15 seconds may damage the brake.

11. Slowly increase the engine rpm to HIGH IDLE. The machine should not move.

12. Reduce the engine speed to LOW IDLE. Move the transmission control to the NEUTRAL position. Engage the parking brake.

13. After testing, lower the work tool to the ground and stop the engine.

14. Engage the parking brake.

Note: If the machine moved during the test, inspect the brake components. Refer to the Testing and Adjusting, "Braking System Troubleshooting" for probable causes. Repair the brake components before you return the machine to operation.

Adjustment of the Service Brake Control

Illustration 1	g01155690
Right Side View

Adjustment of the Service Brake Control Pedal

Use the following procedure in order to adjust the height of the stop.

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Illustration 2	g01373093
View C (1) Stop bolt (2) Locknut (D) 90 ± 1 mm (3.54 ± 0.04 inch)

1. Measure the Dimension (D) . If the dimension is not within the specification, adjustment is necessary.

2. Loosen the locknut (2) .

3. Turn the bolt (1) in order to achieve the dimension (D) .

   Note: Turn the bolt (1) clockwise in order to raise the stop. Turn the bolt (1) counterclockwise in order to lower the stop.

4. Tighten the locknut (2) .

5. Start the engine. Apply the service brakes and release the service brakes.

6. Check the Dimension (D) . Repeat the procedure if dimension (D) is not within the specification.

Adjustment of the Inching Valve Control Cable

Illustration 3	g01155668
View A (F) 4 mm (0.1575 inch) maximum (3) Ball joint (4) Lever

For proper adjustment, the pedal for the service brake must be in the free state. Also, the lever (4) for the inching control must be in the maximum back position.

Use the ball joint (3) in order to adjust the cable.

Note: Do not exceed the maximum range (F) of the ball joint (3) .

Adjustment of the Service Brake Control Cable

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Illustration 4	g01155794
View C (E) 30 ± 1 mm (1.18 ± 0.04 inch) Maximum

Note: 30 ± 1 mm (1.18 ± 0.04 inch) is the maximum pedal travel for full brake engagement.

1. Measure the Dimension (E) . If the dimension is not within the specification, adjustment is necessary.

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Illustration 5	g01155669
View B () Locknut () Rod end

2. Loosen the locknut (6) .

3. Disconnect the Rod End (5) from the brake lever.

4. Turn the Rod End (5) in order to achieve the dimension (E) . Turn (1) 360° in the clockwise direction after the dimension is achieved.

   Note: Turn the Rod End (5) clockwise in order to decrease the dimension (E) . Turn the Rod End (5) counterclockwise in order to increase the dimension (E) .

5. Tighten the locknut (6) .

6. Test the service brake. Refer to Testing and Adjusting, "Service Brake - Test".

Adjustment of the Brake Light Switch

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Illustration 6	g01157839
(7) Nut (8) Limit Switch (9) Nut

1. Loosen the nuts (7) and (9) on the switch (8) .

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Illustration 7	g01158014
(7) Nut (8) Limit Switch (9) Nut (10) Brake pedal (11) Roller

2. Position the switch (8) so that the roller (11) is in contact with the brake pedal (10) .

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Illustration 8	g01158038
(H) Dimension for setting the stroke 2 mm (0.08 inch)

3. Turn the nut (9) on the limit switch (8) clockwise so that the switch strokes (H) 2 mm (0.08 inch).

4. Make sure that the brake lights are off.

5. If the brake lights are off, proceed to Step 6. If brake lights are on, Turn the nut (9) on the limit switch (8) counterclockwise slowly until lights turn off.

6. Tighten the nuts (7) and (9) .