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

Disassembly Procedure

Start By:

1. Remove the service and parking brake (front).

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

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Illustration 1	g00508624

1. Position the service and parking brake on wood blocks, as shown.

2. Remove bolts (1) and the hard washers from the brake anchor.
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   Illustration 2	g00508649

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   Possible injury can result from spring force released when removing the nuts. Spring force will be released when the nuts and the brake anchor are removed. Loosen the nuts evenly, one turn at a time in order to release the spring force.

3. Loosen nuts (2) evenly. Loosen each of the nuts by one revolution before proceeding to the next nut until all the spring pressure has been released.
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   Illustration 3	g00508655

4. Attach Tooling (A) and a suitable lifting device to brake anchor (3), as shown. Remove nuts (2) from the taperlock studs.

5. Remove brake anchor (3) from the ring. The weight of brake anchor (3) is approximately 112 kg (247 lb).

6. Position brake anchor (3) onto a suitable work surface. Remove Tooling (A) and the suitable lifting device.
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   Illustration 4	g00515917

7. Attach Tooling (A) and a suitable lifting device to brake anchor (3). Use Tooling (A) and the suitable lifting device to rotate brake anchor (3), as shown. The weight of brake anchor (3) is approximately 112 kg (247 lb).

8. Remove Tooling (A) and the suitable lifting device from brake anchor (3).
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   Illustration 5	g00508656

9. Install 1/2 inch - 13 NC forcing screws (4) in the piston, as shown. Tighten the forcing screws evenly until there is approximately 25.4 mm (1 inch) between the two pistons.
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   Illustration 6	g00508657

10. Install cotter pin (6) in the hole of spring guide (5). The cotter pin is installed below the piston to hold spring guide (5) in position when the forcing screws are removed from the piston.

11. Repeat Step 10 for the remaining spring guides.

12. Remove 1/2 inch - 13 NC forcing screws (4) from the piston.
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    Illustration 7	g00508658

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    Illustration 8	g00515918

13. Use a soft faced hammer to force the piston downward until pin (7) can be removed from spring guide (5).

14. Repeat Step 13 for the remaining spring guides (5).
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    Illustration 9	g06356552

15. Install Tooling (B) and a suitable lifting device in the piston, as shown. Remove piston (8) from the brake anchor. The weight of piston (8) is approximately 42 kg (93 lb).
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    Illustration 10	g00508662

16. Remove seal ring (9), the seal and seal ring (10), and seal rings (11) from piston (8).
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    Illustration 11	g06356526

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    Possible injury can result from spring force released when removing the piston. Spring force will be released when the nuts are removed. Loosen the nuts evenly, one turn at a time in order to release the spring force.

17. Remove nuts (12). Install Tooling (B) and a suitable lifting device in piston (14). Loosen the remaining nuts that are located below the flange of piston (14) evenly. Loosen each of the nuts by one revolution before proceeding to the next nut.

18. Remove piston (14) and housing (13) as a unit from brake anchor (3). The weight of piston (14) and housing (13) is approximately 69 kg (152 lb).
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    Illustration 12	g06356543

19. Position wood blocks under housing (13) (not shown). Separate housing (13) from piston (14). The weight of piston (14) is approximately 40 kg (88 lb). Remove Tooling (B) and the suitable lifting device from piston (14).
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    Illustration 13	g00508902

20. Remove the seal and seal ring (15) and the seal and seal ring (16) from housing (13).
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    Illustration 14	g00572198

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    Illustration 15	g00515928

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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.

21. Use Tooling (C) to compress spring (17). Remove cotter pin (6) from spring guide (5).

22. Slowly release the tension of spring (17). Remove Tooling (C).

23. Remove spring guide (5) and spring (17) from the piston.

24. Repeat Steps 21 through Steps 23 for the remaining spring guides (5).
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    Illustration 16	g00529608

    Note: Put identification marks on the location of the springs for assembly purposes.

25. Remove seals (18) and springs (19) from brake anchor (3). If necessary, use Tooling (D) (not shown) to remove nine taperlock studs (21).

26. If necessary, use Tooling (D) (not shown) to remove taperlock studs (20).
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    Illustration 17	g00529609

27. Remove damper assembly (22) from ring (23).
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    Illustration 18	g00529611

28. Remove friction disc (24) from ring (23).
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    Illustration 19	g00529614

29. Remove outer plate (25) from ring (23).

30. Repeat Steps 28 and 29 for the remaining friction discs and outer plates.
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    Illustration 20	g00529615

31. Remove damper assembly (26) from ring (23).
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    Illustration 21	g00529639

32. Attach a suitable lifting device to brake hub (27), as shown. Remove brake hub (27) from ring (23). The weight of brake hub (27) is approximately 45 kg (99 lb).
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    Illustration 22	g00529641

33. Remove seal rings (28) from brake hub (27).

34. Remove Duo-cone seal (29) from brake hub (27).
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    Illustration 23	g00529645

35. Attach Tooling (A) and a suitable lifting device to ring (23). Remove bolts (31) and the washers that hold plate (30) to ring (23).

36. Remove ring (23) from plate (21). The weight of ring (23) is approximately 67 kg (148 lb).
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    Illustration 24	g00529646

37. Remove O-ring seal (32) from ring (23).
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    Illustration 25	g06356511

38. If necessary, use Tooling (D) (not shown) to remove five taperlock studs (33) from plate (30). Remove Duo-cone seal (34) from plate (30).