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

Assembly Procedure

Note: Cleanliness is an important factor. Before the assembly procedure, all parts should be thoroughly cleaned in cleaning fluid. Allow the parts to air dry. Wiping cloths or rags should not be used to dry parts. Lint may be deposited on the parts which may cause later trouble.

1. Check all of the O-ring seals and the components for wear or damage.

2. Lubricate all of the O-ring seals lightly with the lubricant that is being sealed.
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   Illustration 1	g00487300

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   Illustration 2	g00487302

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   Illustration 3	g00537689

3. Use Tooling (A) and a suitable hydraulic press in order to install roller bearing cone (30) onto pump drive gear (14).

4. Rotate pump drive gear (14) so that roller bearing cone (29) can be installed. Use Tooling (A) and a suitable hydraulic press in order to install roller bearing cone (29) onto pump drive gear (14).
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   Illustration 4	g00487306

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   Illustration 5	g00487307

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   Illustration 6	g00574396

5. Use Tooling (A) and a suitable hydraulic press in order to install roller bearing cone (27) onto pump drive gear (15).

6. Rotate pump drive gear (15) so that roller bearing cone (28) can be installed. Use Tooling (A) and a suitable hydraulic press in order to install roller bearing cone (28) onto pump drive gear (15).
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   Illustration 7	g00487308

7. Install lockring (24) into pump idler gear (16).
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   Illustration 8	g00487309

8. Lower the temperature of roller bearing cup (25) to a temperature of −40 °C (−40 °F). Use Tooling (A) (not shown) and a suitable hydraulic press in order to install roller bearing cup (25) into pump idler gear (16). Seat roller bearing cup (25) against lockring (24).
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   Illustration 9	g00487310

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   Illustration 10	g00487311

9. Rotate pump idler gear (16) so that roller bearing cup (26) can be installed.

10. Lower the temperature of roller bearing cup (26) to a temperature of −40 °C (−40 °F). Use Tooling (A) and a suitable hydraulic press in order to install roller bearing cup (26) (not shown) into pump idler gear (16). Seat roller bearing cup (26) against lockring (24) (not shown).
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    Illustration 11	g00487318

11. Use Tooling (A) (not shown) and a suitable hydraulic press in order to install roller bearing assembly (21) onto governor control shaft (17).

12. Install spacer (20) onto governor control shaft (17).
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    Illustration 12	g00537690

13. Use Tooling (A) (not shown) in order to install roller bearing assembly (19) into pump idler gear (16).
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    Illustration 13	g00487319

14. Position pump drive housing (1) onto a suitable work bench, as shown.
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    Illustration 14	g00537692

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    Illustration 15	g00537693

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    Illustration 16	g00537694

15. Lower the temperature of roller bearing cups (35) and (36) to a temperature of −40 °C (−40 °F). Use Tooling (A) in order to install roller bearing cups (35) and (36) into pump drive housing (1). Seat bearing cups (35) and (36) against the flanges of pump drive housing (1).
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    Illustration 17	g00487344

16. Rotate pump drive housing (1).
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    Illustration 18	g00487353

17. Remove any burrs from pump drive housing (1) so that the bearing end play will be set properly.
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    Illustration 19	g00574397

18. Install lip seal (32) into pump drive housing (1).

19. Install plug (33) and the O-ring seal into pump drive housing (1).
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    Illustration 20	g00538072

20. Install plug (34) and the O-ring seal into pump drive housing (1).
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    Illustration 21	g00487347

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    Illustration 22	g00537719

21. Use Tooling (A) in order to install seal ring (31) into pump drive housing (1), as shown.
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    Illustration 23	g00486647

22. Position pump drive housing (1) vertically into a suitable fixture or a vise, as shown.
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    Illustration 24	g00487448

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    Illustration 25	g00486613

23. Insert pump idler gear (16) through the lower opening of pump drive housing (1). Position pump idler gear (16) into the center position of pump drive housing (1), as shown.
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    Illustration 26	g00486605

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    Illustration 27	g00487600

24. The following steps illustrate the procedure that is used in order to determine the thickness of shim pack (23):

    1. Insert governor control shaft (17) into pump drive housing (1) without any shims or O-ring seals.

    2. Install four bolts (18) and the washers in order to secure governor control shaft (17) to pump drive housing (1). Tighten four bolts (18) evenly to a torque of 7 ± 1 N·m (5.16 ± 0.74 lb ft).
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       Illustration 28	g00574399

    3. Insert a depth micrometer into one of the holes that is located on governor control shaft (17). Record the measurement. Insert a depth micrometer into the remaining hole that is located on governor control shaft (17). Calculate the average of the two measurements. Record the average measurement.
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       Illustration 29	g00486613

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       Illustration 30	g00487600

    4. Support pump idler gear (16). Remove four bolts (18) and the washers in order to remove governor control shaft (17) from pump drive housing (1). Lower pump idler gear (16).
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       Illustration 31	g00487626

    5. Use an outside micrometer in order to measure the thickness of the flange of control shaft (17) in three equally spaced locations. Calculate the average of the three measurements. Record the average measurement.

    6. Subtract the measurement that was recorded in Step 24.e from the measurement that was recorded in Step 24.c. Record the measurement.

    7. In order to determine the thickness of shim pack (23), subtract −.1 mm (−0.004 inch) from the measurement that was recorded in Step 24.f. This measurement is the required thickness of the shim pack. Use an outside micrometer in order to assemble shim pack (23).
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    Illustration 32	g00537720

25. Install shim pack (23) onto governor control shaft (17).

26. Install O-ring seal (22) onto governor control shaft (17).
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    Illustration 33	g00486613

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    Illustration 34	g00487600

27. Position pump idler gear (16) into the center position of pump drive housing (1), as shown.

28. Insert governor control shaft (17) and the shims into pump drive housing (1). Install four bolts (18) and the washers in order to secure governor control shaft (17) to pump drive housing (1). Tighten four bolts (18) evenly to a torque of 47 ± 9 N·m (34.7 ± 6.6 lb ft).
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    Illustration 35	g00486599

29. Install pump drive gear (14) into the upper opening of pump drive housing (1).
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    Illustration 36	g00486601

30. Install pump drive gear (15) into the lower opening of pump drive housing (1).
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    Illustration 37	g00537722

31. Lower the temperature of roller bearing cup (9) to a temperature of −40 °C (−40 °F). Use Tooling (A) (not shown) in order to install roller bearing cup (9) into bearing cage (6).
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    Illustration 38	g00537724

32. Lower the temperature of roller bearing cup (13) to a temperature of −40 °C (−40 °F). Use Tooling (A) (not shown) in order to install roller bearing cup (13) into cage assembly (3).
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    Illustration 39	g00487453

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    Illustration 40	g00487456

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    Illustration 41	g00537727

33. Use six bolts (5) and the washers in order to install bearing cage (6) onto pump drive housing (1) without any shims or O-ring seals.

34. Use six bolts (7) and the washers in order to install cage assembly (3) onto pump drive housing (1) without any shims or O-ring seals.

35. Tighten six bolts (5) and six bolts (7) evenly until the pump drive gears bind slightly.
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    Illustration 42	g00487484

36. Strike the pump drive gears with a soft faced hammer in order to seat the pump drive gears into the bearing cones. Repeat Step 35.

37. The following steps illustrate the procedure that is used in order to determine the thickness of shim pack (10):
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    Illustration 43	g00537727

    1. Insert a depth micrometer into one of the three holes that are located on bearing cage (6). Record the measurement. Repeat for the remaining two holes. Calculate the average of the three measurements. Record the average measurement.

    2. Remove six bolts (5) and the washers in order to remove bearing cage (6) from pump drive housing (1).

    3. Use an outside micrometer in order to measure the thickness of the shaft flange in three equally spaced locations. Calculate the average of the three measurements. Record the average measurement.

    4. Subtract the measurement that was recorded in Step 37.c from the measurement that was recorded in Step 37.a. Record the measurement. This measurement is the average gap between bearing cage (6) and pump drive housing (1).

    5. In order to determine the thickness of shim pack (10), add 0.1 mm (0.004 inch) to the measurement that was recorded in Step 37.d. This measurement is the required thickness of the shim pack. Use an outside micrometer in order to assemble shim pack (10).
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       Illustration 44	g00537728

    6. Install shim pack (10) onto bearing cage (6). Install O-ring seal (8) onto bearing cage (6). Use six bolts (5) and the washers in order to install bearing cage (6) onto pump drive housing (1). Tighten six bolts (5) to a torque of 47 ± 9 N·m (34.67 ± 6.64 lb ft).

38. The following steps illustrate the procedure that is used in order to determine the thickness of shim pack (12):
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    Illustration 45	g00537727

    1. Insert a depth micrometer into one of the three holes that are located on cage assembly (3). Record the measurement. Repeat for the remaining two holes. Calculate the average of the three measurements. Record the average measurement.

    2. Remove six bolts (7) and the washers in order to remove cage assembly (3) from pump drive housing (1).

    3. Use an outside micrometer in order to measure the thickness of the shaft flange in three equally spaced locations. Calculate the average of the three measurements. Record the average measurement.

    4. Subtract the measurement that was recorded in Step 38.c from the measurement that was recorded in Step 38.a. Record the measurement. This measurement is the average gap between cage assembly (3) and pump drive housing (1).

    5. In order to determine the thickness of shim pack (12), add 0.1 mm (0.004 inch) to the measurement that was recorded in Step 38.d. This measurement is the required thickness of the shim pack. Use an outside micrometer in order to assemble shim pack (12).
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       Illustration 46	g00537729

    6. Install shim pack (12) onto cage assembly (3). Install O-ring seal (11) onto cage assembly (3). Use six bolts (7) and the washers in order to install cage assembly (7) onto pump drive housing (1). Tighten six bolts (7) to a torque of 47 ± 9 N·m (34.67 ± 6.64 lb ft).
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    Illustration 47	g00574402

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    Illustration 48	g00574403

39. Assemble Tooling (B), as shown. Attach Tooling (B) to pump drive housing (1), as shown. Use Tooling (B) in order to measure the end play of pump drive gear (14) and pump drive gear (15). The total end play of pump drive gear (14) and pump drive gear (15) should be between 0.05 mm (0.002 inch) and 0.15 mm (0.006 inch).

    Note: Shim pack (10) and shim pack (23) should be adjusted in order to achieve a total end play between 0.05 mm (0.002 inch) and 0.15 mm (0.006 inch).

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    Illustration 49	g00487499

40. Rotate the gear assemblies in order to check for binding.
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    Illustration 50	g00486591

41. Install yoke assembly (4) onto the spline of pump drive gear (14) that is inside of pump drive housing (1).
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    Illustration 51	g00537725

42. If necessary, install two dowels (2) onto cage assembly (3).

43. Add 1 L (1.057 qt) of clean hydraulic oil to the pump drive after final assembly.

End By:

1. Install the pump drive. Refer to Disassembly and Assembly, "Pump Drive - Install".