784C and 785C Off-Highway Trucks Machine Systems Caterpillar

Disassembly Procedure

Start By:

1. Remove the front air/hydraulic cylinder or the rear air/hydraulic cylinders for the brakes. Refer to either Disassembly and Assembly, "Air/Hydraulic Cylinder (Front Brake) - Remove" or refer to Disassembly and Assembly, "Air/Hydraulic Cylinder - Remove".

Note: Cleanliness is an important factor. Before the disassembly procedure, the exterior of the component should be thoroughly cleaned. This will help to prevent dirt from entering the internal mechanism.

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Illustration 1	g00527121

1. Place cylinder assembly (1) onto a suitable work bench.

2. Remove eight nuts (2).

3. Remove cylinder assembly (3).
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   Illustration 2	g00527277

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   Illustration 3	g00527122

4. Remove limit switch (5) and the O-ring seal from cylinder assembly (1).

5. Remove indicator rod (4) and O-ring seal (7).

6. Position cylinder assembly (1) into a suitable bench vise (not shown). Use the bench vise (not shown) in order to keep the spring in compression until locknut (6) is removed.
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   Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

7. Remove locknut (6). Use the bench vise (not shown) to slowly release the spring tension. Remove cylinder assembly (1) from the bench vise (not shown).
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   Illustration 4	g00527123

8. Remove piston assembly (8) from rod (9).

9. Remove spring (10).
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   Illustration 5	g00527126

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   Illustration 6	g00527128

10. Remove six bolts (11) and the washers from piston assembly (8).

11. Remove retaining ring (12), spring (13), seal (14), and piston (15).

12. Remove two O-ring seals (16) from retaining ring (12).
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    Illustration 7	g00527129

13. Remove purge screw (17) from end cap (18).

14. Remove end cap (18) from cylinder tube (19).
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    Illustration 8	g00527131

15. Remove piston body (20) and rod (9) from cylinder tube (19) as a unit.

16. Remove cylinder tube (19) from plate (21).
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    Illustration 9	g00527153

17. Use Tool (A) (not shown) in order to remove retaining ring (23) from body (20).

18. Remove rod (9), valve (22), and seal (24) from body (18).
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    Illustration 10	g00527154

19. Remove two seals (25) from cylinder tube (19).

20. Remove two nuts (26) from cylinder tube (19).
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    Illustration 11	g00527155

21. Remove two seals (27) from plate (21).