990K Wheel Loader and 844K Wheel Dozer Machine Systems Caterpillar

Disassembly Procedure

Start By:

1. Remove the piston pump.

Show/hide table

Illustration 1	g06224966

1. Secure pump body (1) to Tooling (A) or a suitable workbench.

2. Remove bolts (2) and valve assembly (3).
   Show/hide table

   Illustration 2	g06225119

3. Remove gasket (4), plug (5), and the seal.
   Show/hide table

   Illustration 3	g06225123

4. Remove plug (6) from valve assembly (3).
   Show/hide table

   Illustration 4	g06225130

   Show/hide table

   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.

5. Remove O-ring seal (7) from plug (6).
   Show/hide table

   Illustration 5	g06225127

6. Measure height of adjustment screw (8) from plug (6) for assembly purposes.

7. Remove nut (9).
   Show/hide table

   Illustration 6	g06225138

8. Remove plate (10) from plug (6).

9. Remove adjustment screw (8) in the direction shown.
   Show/hide table

   Illustration 7	g06225139

10. Remove O-ring seal (12) and backup ring (11) from adjustment screw (8).
    Show/hide table

    Illustration 8	g06224971

11. Remove O-ring seal (13) and coupler (14) from the piston pump.
    Show/hide table

    Illustration 9	g06224976

    Show/hide table

    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.

12. Remove bolts (15) and pump flange (16) from pump body (1).
    Show/hide table

    Illustration 10	g06224997

13. Remove O-ring seal (17) and control plate (18) from pump flange (16).

14. Remove bearing cup (19) from pump flange (16).
    Show/hide table

    Illustration 11	g06225002

15. Remove bearing cone (20) from shaft assembly (21).
    Show/hide table

    Illustration 12	g06225006

16. Remove shim (22) from shaft assembly (21).

17. Remove O-ring seal (23) from pump body (1).
    Show/hide table

    Illustration 13	g06225156

18. Rotate pump body (1) and remove barrel assembly (24).
    Show/hide table

    Illustration 14	g06225157

19. Remove pistons (25), piston retainer (27), and guide (26) from barrel assembly (24).
    Show/hide table

    Illustration 15	g06225181

    Show/hide table

    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.

20. Use Tooling (B), Tooling (C), and a suitable press to compress the barrel spring.

21. Remove retaining ring (28) from barrel assembly (24).
    Show/hide table

    Illustration 16	g06225182

22. Remove spring (31), spacer (30), and pins (29) from barrel assembly (24).
    Show/hide table

    Illustration 17	g06225183

    Show/hide table

    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.

23. Remove plugs (33) and the O-ring seals from pump body (1).

24. Remove plug (32) and the O-ring seal.
    Show/hide table

    Illustration 18	g06225185

25. Remove plug (34) from pump body (1).
    Show/hide table

    Illustration 19	g06225186

26. Remove swashplate (35) from pump body (1) by lifting from the side marked (X).
    Show/hide table

    Illustration 20	g06225187

27. Remove shaft assembly (21) and spring (37) from pump body (1).

28. Remove screws (36) and bearings (38) from the pump body.
    Show/hide table

    Illustration 21	g06225188

29. Use Tooling (C) and a suitable press to remove bearing cone (39) from shaft assembly (21).
    Show/hide table

    Illustration 22	g06225190

30. Remove retaining ring (40) and lip seal (41) from pump body (1).

31. Remove bearing cup (42) from pump body (1).