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

Assembly Procedure

Note: Cleanliness is an important factor. Before assembly, thoroughly clean all parts 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. Replace the components, if necessary.

2. Lubricate all of the O-ring seals lightly with the lubricant that is being sealed.
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   Illustration 1	g02715743

3. Install bolt dampers (20A) into oil pump body (15) to a depth of 7.5 ± 0.50 mm (0.30 ± 0.020 inch).

4. Install bolt dampers (20B) into oil pump body (15) to a depth of 1.50 ± 0.5 mm (0.30 ± 0.020 inch).
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   Illustration 2	g02715763

   Note: Do not lower the temperature of bearings (19).

5. Use Tooling (B) and a suitable pump in order to install bearings (19) into pump body (15). The joint surfaces of the bearings must be 30 ± 15 degrees from the centerline through the bearing bores. The joint surfaces must be toward Outlet Port (X). Make sure that bearings (19) are 1.50 ± 0.25 mm (0.059 ± 0.010 inch) below the machined surface of pump body (15). The bearing inside diameters must be 31.798 ± 0.039 mm (1.2519 ± 0.0015 inch) after installation. If, after three attempts the bearing diameters do not measure 31.798 ± 0.039 mm (1.2519 ± 0.0015 inch) replace pump body (15).
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   Illustration 3	g00564577

6. Install pump gear assembly (10) and gear assembly (11) into pump body (15), as shown.
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   Illustration 4	g02694257

7. Install woodruff key (12) (not shown) into gear assembly (10).

8. Align the slot on gear (18) with woodruff key (12) (not shown). Install gear (18) onto gear assembly (10).

9. Install gear (18) onto gear assembly (11).

10. Install dowels (14) into oil pump body (16).

    Note: Dowels (14) should protrude from pump body (16) by a distance of 0.190 mm (0.0075 inch).

11. Install pump body (16) and the O-ring seal onto pump body (15), as shown.
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    Illustration 5	g02715774

    Note: Do not lower the temperature of bearings (17).

12. Use Tooling (B) to install bearings (17) into pump cover (4). The joint surfaces of the bearings must be 30 ± 15 degrees from the centerline through the bearing bores. The joint surfaces must be toward Outlet Port (X). Make sure that the bearings are 1.50 ± 0.25 mm (0.059 ± 0.010 inch) below the machined surface of pump cover (4). The bearing inside diameters must be 31.798 ± 0.039 mm (1.2519 ± 0.0015 inch) after installation. If, after three attempts the bearing diameters do not measure 31.798 ± 0.039 mm (1.2519 ± 0.0015 inch) replace pump cover (4).
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    Illustration 6	g00564575

13. Install pump cover (4) and the O-ring seal onto pump body (16), as shown.
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    Illustration 7	g00564574

14. Install dowels (14) into pump body (5).

    Note: Dowels (14) should protrude from pump body (16) by a distance of 0.19 mm (0.0075 inch).

15. Install pump body (5) and the O-ring seal onto pump body (15).
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    Illustration 8	g00564552

16. Install woodruff key (12) (not shown) into gear assembly (10).

17. Align the slot on gear (13) with woodruff key (12) (not shown). Install gear (13) onto gear assembly (10).

18. Install gear (13) onto gear assembly (11).
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    Illustration 9	g02715781

    Note: Do not lower the temperature of bearings (9).

19. Use Tooling (B) and a suitable pump to install bearings (9) into pump cover (7). The joint surfaces of the bearings must be 30 ± 15 degrees from the centerline through the bearing bores. The joint surfaces must be toward Outlet Port (X). Make sure that the bearings are 1.50 ± 0.25 mm (0.059 ± 0.010 inch) below the machined surface of pump cover (7). The bearing inside diameters must be 31.798 ± 0.039 mm (1.2519 ± 0.0015 inch) after installation. If, after three attempts the bearing diameters do not measure 31.798 ± 0.039 mm (1.2519 ± 0.0015 inch) replace pump cover (7).
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    Illustration 10	g00564550

20. Use two bolts (6) and the hard washers to install pump cover (7). Use four bolts (8) and the hard washers to install pump cover (7) to pump body (5).
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    Illustration 11	g00564549

21. Use bolts (2) to install plate (3) and the O-ring seal to pump cover (4).

22. Before the gear pump is tested, lubricate the gear pump with oil. You should be able to rotate the gear pump with hand pressure.

End By:

1. Install the gear pump (torque converter and parking brake release). Refer to Disassembly and Assembly, "Gear Pump (Torque Converter and Parking Brake Release) - Install".