STANADYNE FUEL SYSTEM MODEL DB4 PUMP Caterpillar

1. Use 4C6627 Bearing and Seal Installer (P) to install lower seal (4).

2. Install spacer (3) in housing.

3. Use 4C6627 Bearing and Seal Installer (P) to install upper seal (2) in housing.

4. Use 4C6627 Bearing and Seal Installer (P) to install bearing (1) in the housing.

NOTE: Make sure all pump components are wet with test oil throughout the entire assembly procedure.

5. Install brass thrust snap ring (5).

6. Install shaft assembly (6) from front of pump.

7. Insert thrust washer (7) in the proper orientation to the shaft (6).

8. Insert spring washer (8) and snap ring (9). Make sure the mark on the end of the shaft is orientated towards the top of the pump.

9. Install four plungers (12), four rollers (11), four shoes (10), two leaf springs (13), and two screws (14).

10. Put 4C6845 Roller Setting Fixture (15) in a vise. Put rotor assembly (16) in the fixture.

11. Using 345 to 415 kPa (50 to 60 psi) air pressure, check the roller-to-roller dimension and check the centrality. Set the roller-to-roller dimension to the TMI specification.

NOTE: Using the Tool and the specification furnished by Caterpillar Service Technology Group, the roller-to-roller dimension can be obtained. To set the roller-to-roller dimension to the specification, turn the leaf adjusting screws clockwise (inward) to increase and counterclockwise (outward) to decrease the roller-to-roller dimension.

NOTE: If the roller-to-roller dimension is set correctly no additional test bench adjustments should be necessary.

12. Install rubber grommets (17) in rotor assembly (16). Install rotor assembly (16) on retainer assembly (18).

13. Install retainers (20) and retainer clips (19).

14. Install cam ring (21).

NOTE: Position cam ring into original position as noted when disassembled.

15. Rinse the hydraulic assembly in clean calibrating oil. Carefully, insert the rotor assembly (16) into the head assembly (22).

16. Install the liner locating ring and two rotor retainers (23).

17. Install delivery valve (27), spring (26), and a new delivery valve stop (25) and screw (24). Tighten screw (24) to a torque of 9.5 to 10 N·m (84 to 90 lb in).

18. Install a new transfer pump end cap seal (28) into the head.

NOTE: The seal has an oval cross section and can be readily identified by rolling it between your fingers. Maker sure the seal is placed all the way into its locating groove.

19. Insert transfer pump liner (30) so that the slot is in line with the hole which the regulator assembly roll pin enters.

20. Install four blades (29) and two springs (not shown).

NOTE: Oversize blade should be fitted into the proper slot. It is permissible to use both oversize and standard size blades in the same rotor. Be careful not to lose the alignment of the hole.

21. Install seal (35) into regulator (34). Install piston (33), spring (32), plug (31).

22. Install regulating assembly (37).

23. Install inlet filter screen (36).

24. Install cap (38). Rotate the cap counterclockwise until a slight "click" is heard; then turn the cap clockwise by hand until tight.

NOTE: Before assembly, apply 5P0960 Molybdenum Grease to the outside of the pressure plate and to the threads of the end cap.

25. Turn head-assembly over and install six weights (39).

26. Install washer (not shown) and thrust sleeve (40) in the center of the weights on the groove.

NOTE: The two deep grooves of the thrust sleeve should face upward as assembled.

NOTE: When assembled, sight across the tops of the assembled weights. They all should be level and resting against the thrust sleeve.

27. Install governor arm (41), pivot shaft (42), new O-ring seals (43), and nuts (44). Tighten nuts to a torque of 2 to 3 N·m (18 to 27 lb in).

NOTE: When assembling the pivot shaft, make sure the knife edge mates with the groove in the governor arm.

28. The hydraulic head and rotor assembly including the transfer pump assembly, cam ring, and governor assembly, are now ready to put into the housing. Install a new seal (45) on the hydraulic head after first greasing it slightly. Apply a light film of clean grease around the inside edge of the housing and tilt the housing slightly downward at the rear to aid in assembly. Rotate the cam ring so that the unthreaded hole is in line with the metering valve bore. This will insure proper position of the cam ring. Grasp the hydraulic head firmly in both hands and insert it into the housing bore with a slight rotary motion. Do not force. If the assembly should jam during insertion, withdraw, and start over.

NOTE: Exercise care not to insert the head assembly too far into the housing. Pushing the head in too far will damage the seal on the hydraulic head and result in leakage. Turn drive shaft if needed to align tang with slot in head.

29. Rotate head assembly until the head locking screw holes line up with there corresponding holes in the housing. Install two head locking screws (46) finger tight.

30. Use 4C6989 Socket (D) and torque the end cap to 41 to 50 N·m (30 to 37 lb ft).

31. Install seal, plate (48), and screw to cap (47). Tighten screw to a torque of 8 to 9 N·m (72 to 80 lb in).

32. Install vent wire screw assembly (49). Tighten screw to a torque of 3 to 3.5 N·m (27 to 31 lb in).

33. Install metering valve assembly (50).

NOTE: Make sure that none of the components are distorted during assembly.

NOTE: Photos and steps on this page are for the Mechanical Governor.

34. Engage the linkage hook (53) on the governor arm (41) and install on the metering valve assembly (50) arm pin.

35. Depress metering valve assembly (50), install guide stud (51) and guide stud washer (52), through the back of the housing.

36. Install spring and components (54) on guide stud (51).

NOTE: Check and make sure that there is free movement on all of the governor components.

37. Install new washers and seals on throttle shaft assembly (55). Install throttle shaft assembly (55) through shaft lever (56). Install throttle shaft assembly. Install key (57)

38. Install new Mylar washers and seals to the throttle and shutoff shafts. Apply a light film of grease to each seal. Assemble the throttle shaft assembly partially through its bore in the housing. Slide the throttle shaft lever over the throttle shaft so that the projection in the throttle shaft lever bore engages the rear keyway on the shaft. Position the forked end of the throttle lever so that it straddles the guide stud. Assemble the shutoff shaft assembly with a slight rotary motion, so as not to damage the seal. If the throttle shaft lever is correctly installed, rotating the throttle shaft assembly to the rear will cause compression of the governor spring.

NOTE: Photos and steps 39 through 49 are for the Speed Droop Governors.

39. Thread governor control spring (59) five full coils onto control rod (58).

40. Install governor control rod (58) through threaded hole from inside of the pump housing. Put governor control spring (59) over tabs on governor arm (41).

41. Put control guide (61) with washer in place over the end of control rod assembly (60). Thread into the housing finger tight while pushing down on metering valve assembly (50).

42. Put the governor control rod pin into the hole at the end of the governor control rod (58).

43. Install O-ring seal into the seal groove on adjusting cap assembly (63). Align slot in adjusting cap assembly (63) with governor control rod pin and slide into control rod assembly (60). Thread locking cap (62) onto control rod assembly (60) and tighten while supporting the control rod assembly.

44. Put damper spring (65) on damper piston (64). Put the end of damper spring (65) on governor arm (41).

45. Put damper barrel assembly (66) over the damper piston and damper spring.

46. Slide throttle shaft assembly (67) through the damper barrel assembly (66), throttle shaft spacer (68), and throttle lever (69). Install key (70) in throttle shaft assembly (67).

47. With throttle shaft assembly in low idle position and the governor control spring relaxed, the forked end of the throttle lever should straddle and engage the flats on the control rod bushing.

48. Adjust the low idle screw until the forks of the throttle lever make contact with the flats on the control rod bushing. Tighten low idle locknut to 3.4 to 4.0 N·m (30 to 35 lb in).

49. Turn adjusting cap counterclockwise (from transfer pump end) to end of adjustment then turn clockwise 1/16 of turn. The speed droop is now positioned for minimum droop.

50. Install seal on head locating screw (72). Apply a small amount of grease to the head locating screw (72) and install. Tighten screw (72) to a torque of 20 to 25 N·m (15 to 18 lb ft). Tighten the two head locking screws (46) from step 29 to a torque of 20 to 25 N·m (15 to 18 lb ft).

NOTE: If screw (72) is not properly seated, the seal may be sheared during tightening.

51. Install two O-ring seals (74) on spring side guide advance piston hole plug (73). Install piston retainer (80) on piston (77). Install two O-ring seals (81) on power side advance piston hole plug (78).

52. Install spring guide (75), spring (76), into spring side advance piston hole plug (73) and install into housing.

53. Install piston ring (80), piston (77) into power side advance piston hole plug (78) and into housing.

54. Install cam plug (79) with tweezers (82).

55. Install advance plug (83). Tighten the advance plug to a torque of 8 to 11 N·m (72 to 99 lb in). Tighten plugs (73 and 78) to a torque of 24 to 30 N·m (18 to 22 lb ft).

56. Invert the pump and fixture in the vise. Prior to measuring and adjusting the linkage gap.

a. The torque screw (if used) should bee backed out.

b. With the throttle lever in the wide open position, push the vertical tab of the linkage hook toward the drive end of the pump, and rotate the drive shaft in the proper direction of rotation until a slight "click" is heard and the toes of the governor arm engage slots in the thrust sleeve.

c. Loosen the adjusting screw and slide linkage to maximum open length.

d. With the throttle lever held in the wide open position, use 4C8124 Kit-Linkage (N) to set the clearance between the rear of the throttle shaft and the vertical tab on the linkage hook. (Refer to pump specifications for correct dimensions).

e. Insert the preferred size step of the gauge between the throttle shaft and the vertical tab of the linkage hook.

f. Push on the linkage hook vertical tab to close the gap down to a thickness of the gauge which should also push the governor arm forward fully seating the governor weights in their retainer.

g. While pinching the gauge between the throttle shaft and the vertical tab, tighten the adjusting screw.

h. Check the setting by pushing on the vertical tab of the linkage hook and inserting 4C8124 Kit-Linkage (N) to determine if the gap is within tolerance. If not, reset as outlined in Steps a through g.

NOTE: When the linkage is adjusted, the pump must be tested to specifications.

57. Hold throttle open. Push metering valve back. Check clearance. If correct, adjust screw until clearance is correct, then tighten.

58. Compress both sides of the throttle and shutoff shaft and install a new shutoff cam and/or a new throttle shaft retainer clip as needed with the straight inner edge engaging the slot. The cam or clip should snap into position when installed correctly.

59. Install solenoid assembly (84) and gasket.

60. Install two new seals (85), two washers (86), two nuts (87), two electrical plugs (88), two washers (89), and two nuts (90).

61. Install gasket (92) to cover (91). Install cover, making sure hook on solenoid assembly (84) goes under the lever on the governor control. Install three bolts and washers. Tighten three bolts to a torque of 4.0 to 5.0 N·m (35 to 45 lb in) using 4C6624 Pin.

62. Install timing cover (93) and gasket. Remove pump from holding fixture and install pump flange seal.

63. Install aneroid and aneroid bucket (94). Install fitting (95) in housing.

64. Put rod (96) in hole (97) of lever (98). Install the clip on rod (96).

NOTE: For the adjustment procedure for the aneroid, see the Testing and Adjusting section of this module.