2003/07/21 Caterpillar

Wheel Loader:

994 (S/N: 9YF1-UP)

994D (S/N: 3TZ1-UP)

Service Magazine SEPD0692, 21 July 2003, "An Adjustment Procedure is Used for the Left Brake Pedal Assembly". Disregard this article. Refer to the following information.

Note: The 994 Wheel Loaders that have been converted with the Steering Transmission Integrated Control or the STIC retrofit kit are the applicable machines for the adjustment procedure for the brake pedal. If a 994 Wheel Loader has not been converted to the STIC system, the following procedure may be disregarded.

The 125-8249 Left Brake Pedal that is used on the 994 and the 994D Wheel Loader can be adjusted in order to provide the correct output signal for the 219-2386 Position Sensor. The 125-8249 Left Brake Pedal and the 9K-4934 Lever are not positioned correctly on the splines of the 172-5749 Shaft in relation to the tang that is located on the end of the shaft. As a result, the 219-2386 Position Sensor will not operate within the correct signal range.

The new adjustment procedure is effective with (S/N: 3TZ1-UP).

In order to adjust the sensor output, the left pedal assembly will need to be partially disassembled. This operation will restore the proper spring tension. The 172-5749 Shaft will need to be rotated in order to align the tang that is located on the end of the shaft with the position sensor. Follow the steps that are given below in order to adjust the left brake pedal assembly.

Adjustment Procedure

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Illustration 1	g01009319

1. Remove two bolts (2) that retain position sensor (1) in place. Remove the position sensor (1) from the pedal assembly.

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Illustration 2	g01009353

2. Remove pedal (3) from the shaft (not shown) by removing the retaining bolt.

3. Ensure that you align the plate that holds the bumper on the floor of the cab with the plate that is fastened to the side of the cab. The plates must be parallel. Align the plates, if necessary.

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Illustration 3	g01010162

4. Place a straightedge on the top surface of tang (4). This will determine if the shaft is correctly aligned. Refer to Illustration 3, if necessary.

5. The straightedge should be along the bottom edge (7 O' Clock position) of the upper mounting hole. This will indicate if tang (4) is properly aligned. If tang (4) is not in the correct alignment, proceed to Step 6.

6. Remove bumper (5) from the floor of the cab.

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Illustration 4	g01009447

7. Detach spring (6) from the floor of the cab.

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Illustration 5	g01009471
Lever (10) is removed from the shaft for clarity.

8. Remove cotter pin (8) and washer (9) from pin (7) .

9. Remove pin (7) from lever (10). Ensure that you remove two washers (12) with pin (7). Allow brake cable (11) to hang away from lever (10) .

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Illustration 6	g01009582

10. Loosen bolt (15) that retains lever (10) onto shaft (13). This will allow shaft (13) to slide freely to the left.

11. Partially remove shaft (13) from the brake assembly by pulling shaft (13) to the left.

    Note: Shaft (13) must be pulled out far enough to release lever (10) from the shaft. This will enable the shaft to be correctly positioned in Step 15.

12. Ensure that you retain washers (14) when you remove shaft (13) .

13. Allow lever (10) to hang free from shaft (13) at this time.

14. Insert shaft (13) into the pedal assembly in order to check the alignment.

15. Rotate shaft (13) and recheck the alignment without lever (10) in place. Refer to Step 4 in order to check the alignment of shaft (13) .

16. Tang (4) should now be in alignment with upper screw (1). Tang (4) should point to upper sensor screw (1). If tang (4) is not in alignment, you must perform Step 6 through Step 15 again.

    Note: You may wish to partially insert a screw (1) into the upper hole in order to help achieve an accurate alignment.

17. When you have achieved the proper alignment, proceed to Step 18.

18. Place an alignment mark on the locknut (not shown) in order to ease reassembly of the pedal and the shaft.

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Illustration 7	g01009623
The proper alignment is shown between bumper (5) and lever (10) .

19. Replace bumper (5) that is located on the floor of the cab.

20. You must now reassemble lever (10) onto aligned shaft (13). Pull shaft (13) to the left. Replace lever (10) onto shaft (13). Ensure that you maintain the alignment marks that were placed on the locknut in Step 18.

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Illustration 8	g01009582

21. When you reassemble lever (10) onto shaft (13), use Illustration 7 as a guide. Do not tighten bolt (15) that locks lever (10) in position at this time. Lever (10) must rest flat against bumper (5) .

    Note: If the alignment between bumper (5) and lever (10) cannot be achieved, lever (10) must be removed and the process repeated again until the alignment is correct. If the alignment is correct, proceed to Step 22.

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Illustration 9	g01009471
Lever (10) is removed from the shaft for clarity.

22. You must now verify that the brake assembly will have the correct spring tension. In order to check spring tension, temporarily assemble cable (11) to lever (10) by using pin (7) and cotter pin (8) .

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Illustration 10	g01009447

23. Assemble spring (6) onto the hook that is located on the floor. Attach the opposite end of the spring (6) onto the pedal assembly.

24. Spring (6) should have tension at rest. If spring (6) does not have the proper tension, lever (10) must be rotated around the shaft while you maintain the alignment of the tang that was set in Step 15. This process must be performed until spring (6) has the proper tension.

25. If spring (6) does not have the proper tension, lever (10) must be rotated around the shaft until you achieve the proper spring tension. Ensure that you maintain the alignment of the tang until spring (6) is assembled with tension.

26. When you have verified that the spring has the proper tension, remove spring (6). Remove cotter pin (8) and pin (7) in order to release cable (11) from lever (10) .

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Illustration 11	g01010112

27. Remove plate (17) that retains bumper (5). Allow lever (10) and shaft (13) to hang away from the pedal assembly. This will allow you to properly align the edge of lever (10) with the edge of plate (15) .

28. Place position sensor (2) on the tang of shaft (13). Position sensor (2) must be oriented so that the wiring harness is facing upward. Use Illustration 11 as a guide, if necessary.

29. Secure position sensor (2) to plate (16) by using two screws (1) .

30. Install plate (17) that was removed in Step 27.

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Illustration 12	g01009471
Lever (10) is removed from the shaft for clarity.

31. Install pin (7) into lever (10). Ensure that you install two washers (12) with pin (7) .

32. Install cotter pin (8) and washer (9) onto pin (7) .

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Illustration 13	g01009447

33. Install spring (6) onto the floor of the cab.

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Illustration 14	g01009582

34. Install bolt (15) that locks lever (10) onto shaft (13). Tighten the bolt to a torque of 136 ± 14 N·m (100 ± 10 lb ft).

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Illustration 15	g01013008

35. Assemble pedal (3) onto shaft (13). Ensure that dimension (A) is 83 mm (3.25 inch). Tighten the bolt that retains pedal (3) to shaft (13) .

    Note: Dimension (A) is the distance from the underside of pedal (3) to the top surface of plate (17) .

36. The sensor may be tested by using an Ohmmeter. Set the meter to the "Hz" setting. Ensure that you set the Ohmmeter to read "DC" volts. When the pedal is at rest, the meter should read 30 Hz. When the pedal is completely depressed, the meter should read 55 Hz to 58 Hz.

37. If the sensor should read a low value, perform the following checks:
    • Check the tension of spring (6) .

    • Move the plate in the up direction.

38. If the sensor displays the correct value but spring (6) is not tight perform the following procedure. The lever (10) must be moved one spline or two splines. This will provide the proper tension on the spring.