Water Pump - Overhaul Procedures

BULLETIN NUMBER
SB389-01-009

ISSUE DATE
July 13, 1989

GROUP
ENGINE

WATER PUMP REBUILDING PROCEDURE
(4ZD1/4ZE1 ENGINE)

VEHICLES AFFECTED

All Isuzu models with 4ZD1 or 4ZE1 engine.

SERVICE INFORMATION

A filled water pump assembly may be rebuilt and reinstalled into the vehicle, if the pump housing and fan hub have not been damaged.

This Service Bulletin contains the procedure for rebuilding the water pump assembly, using a Water Pump Repair Kit.

SERVICE PROCEDURE





Refer to Figure 1 for water pump assembly parts identification.

1. Remove the bearing set screw.

2. Heat the pump body in hot water (approx. 120 degrees F) for about 10 minutes.

3. Using a bench press and a bearing separator, remove the following parts from the pump body:

a. Remove the impeller.

b. Remove the bearing unit.





c. Remove the fan hub from the bearing unit (Figure 2).

d. Remove the thrower and the main shaft seal.

e. Remove the seal from the impeller.

4. Inspect the pump housing and fan hub. The water pump must be replaced if the fan hub threads are damaged, or if there are any visible cracks in the housing or fan hub.

5. Clean the pump housing and fan hub by immersing in solvent cleaner. Rinse thoroughly with water, then air dry.

Replace the bearing unit, seal unit, impeller and seals with parts provided in the Water Pump Repair Kit.

6. Heat the pump body in hot water (approx. 120 degrees F) for about 10 minutes.





7. Press the new bearing unit into place, aligning the bearing set screw hole with the screw hole in the pump body (Figure 3).

Install the set screw to secure the bearing unit to the pump body.





8. Press the fan hub into place. The distance from the fan hub upper face to the pump body lower face should be 92.6 +/- 0.3 mm (3.65 +/- 0.01 in.). See Figure 4.

9. Install the new thrower onto the impeller side of the bearing. Press the new seal unit into place, with the spring facing toward the impeller.

NOTE
Use care not to touch seal surfaces. Handle seals by edges only.

10. Heat the new impeller in hot water (approx. 120 degrees F) for about 10 minutes.

11. Install the new seal into the impeller, with the white seal facing out.





12. Press the impeller into place, flush with the end of the bearing shaft. The distance from the pump body lower face to the impeller blade upper corner should be 7.6 +/- 0.2 mm (0.3 +/- 0.01 in.). See Figure 5.





13. Inspect the fan hub fitting face run-out by turning the fan hub (Figure 6). Run-out limit is 0.1 mm (0.0039 in.).

14. Check that the fan hub can be rotated smoothly by hand.





PARTS INFORMATION





FLAT RATE MANUAL UPDATE INFORMATION