Challenger 35, Challenger 45 and Challenger 55 Agricultural Tractors Machine Systems Caterpillar

Disassembly Procedure for (PIN: 8DN620-UP; 1DR1394-UP; 7DM641-UP)

Start By:

1. Remove the steering motor. Refer to Disassembly and Assembly, "Steering Motor - Remove" for the machine that is being serviced.

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	g00565371

1. Put tape on the splined shaft in order to protect the seal.

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Illustration 2	g00565413

2. Tap the cover with a plastic hammer in order to release the pressure against retaining ring (1) .

3. Use Tooling (A) in order to remove retaining ring (1) .

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Illustration 3	g00565415

4. Pry front cover (2) off with two screwdrivers.

5. Remove the O-ring seal and the shim washers from the back of the cover.

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Illustration 4	g00565417

Note: The drive shaft seal (3) will be destroyed if the seal is removed from the front cover. If necessary, remove the seal.

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Illustration 5	g00565419

6. Mark the position of the head in relation to the motor housing. Remove six allen head screw with lockwashers (4) and head (5) from the motor housing.

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Illustration 6	g00565421

Note: When the parts are separated from each other the small washer (6) that is located in the center will fall.

7. Note the position of locating pin (7) on flushing valve plate (8) .

8. Remove flushing valve plate (8) .

9. Remove O-ring seal (9) .

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Illustration 7	g00565424

10. Use a seal pick and compress the retainer and spring (10) in order to start dowel pin (11) out of the bore. Repeat this procedure on the other side.

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Illustration 8	g00565427

11. Remove dowel pin (11) with pliers, as shown. Repeat this procedure on the other side.

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Illustration 9	g00565429

12. Use needle nose pliers in order to hold center pin (12), as shown. Apply pressure to the right side away from the bushing, the spring and the retainer. Compress the retainer and the spring with a seal pick. This will allow bushing (13), the spring and retainer (10) to be removed.

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Illustration 10	g00565430

13. Remove center pin (12) to the right. Remove bushing (13), the spring and retainer (11) .

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Illustration 11	g00565432

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Illustration 12	g00565433

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NOTICE
Use only a puller such as Tooling (B) to remove the rotary group. Do not use a slidehammer type puller or damage to the motor may result.

14. Use Tooling (B) in order to remove the rotary group from the motor housing. The cylinder barrel must not bind as the cylinder barrel is pulled through the motor housing.

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Illustration 13	g00565434

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Illustration 14	g00565436

Note: Mark the piston in relation to the barrel.

15. Remove Tooling (B) from rotating group (14) .

16. Pull barrel (15) from the drive shaft and piston assembly (16) .

Note: Note the position and the location of the spring washers.

17. Remove six spring washers (17) and spacer (18) from the center pin bore of barrel (15) .

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Illustration 15	g00565438

18. Use a section of pipe or wood blocks. Put the drive shaft and piston assembly in position, as shown.

19. Pistons (19) must be in a perpendicular position to retaining plate (20). Remove the pistons by pulling the pistons straight out of the retaining plate. Remove all seven pistons. The center pin cannot be removed at this time.

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Illustration 16	g00565439

20. Check all seven pistons at area (X) for scratches and pitting. If necessary, make replacements.

21. Use a screwdriver and remove piston rings (21) from the piston.

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Illustration 17	g00565442

22. Remove seven screws (22) that hold the retainer plate to the drive shaft assembly. The screws were installed with 9S-3263 Thread Lock Compound. Use impact on the screw heads in order to break the seal. Remove the screws by using additional leverage on the screwdriver, as shown.

23. Remove the retainer plate, center pin (23), and the retaining washer that holds the center pin (23) in place.

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Illustration 18	g00565443

24. Check center pin (23) for scratches or pitting at areas (Y). If necessary, replace center pin (23) .

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Illustration 19	g00565445

25. Use Tooling (C) in order to remove the spanner nut from shaft (24) .

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Illustration 20	g00565447

26. Press two bearings (25) and (26) from shaft (24) .