Oil Pump Disassembly

DISASSEMBLY
1. Mark position of support in oil pump body for assembly alignment reference. Use scriber or paint to make alignment marks.
2. Place pump body on two wood blocks.





3. Remove reaction shaft support bolts and separate support from pump body (Fig. 112).





4. Remove pump inner and outer gears (Fig. 113).





5. Remove O-ring seal from pump body (Fig. 114). Discard seal after removal.
6. Remove oil pump seal with Remover Tool C-3981. Discard seal after removal.

CLEANING
Clean pump and support components with solvent and dry them with compressed air.

INSPECTION
Check condition of the seal rings and thrust washer on the reaction shaft support. The seal rings do not need to be replaced unless cracked, broken, or severely worn. Inspect the pump and support components. Replace the pump or support if the seal ring grooves or machined surfaces are worn, scored, pitted, or damaged. Replace the pump gears if pitted, worn chipped, or damaged. Inspect the pump bushing. Then check the reaction shaft support bushing. Replace either bushing only if heavily worn, scored or damaged. It is not necessary to replace the bushings unless they are actually damaged. Clearance between outer gear and reaction shaft housing should be 0.010 to 0.063 mm (0.0004 to 0.0025 inch). Clearance between inner gear and reaction shaft housing should be 0.010 to 0.063 mm (0.0004 to 0.0025 inch). Both clearances can be measured at the same time by installing the gears in the pump body and measure pump component clearances as follows:

1. Position an appropriate piece of Plastigage across both gears.
2. Align the plastigage to a flat area on the reaction shaft housing.
3. Install the reaction shaft to the pump housing.





4. Separate the reaction shaft housing from the pump housing and measure the Plastigage following the instructions supplied with it. Clearance between inner gear tooth and outer gear should be 0.051 to 0.19 mm (0.002 to 0.0075 inch). Measure clearance with an appropriate feeler gauge (Fig. 115). Clearance between outer gear and pump housing should be 0.10 to 0.229 mm (0.004 to 0.009 inch). Measure clearance with an appropriate feeler gauge.

ASSEMBLY
1. Lubricate pump gears with transmission fluid and install them in pump body
2. Install thrust washer on reaction shaft support hub. Lubricate washer with petroleum jelly or transmission fluid before installation.
3. If reaction shaft seal rings are being replaced, install new seal rings on support hub. Lubricate seal rings with transmission fluid or petroleum jelly after installation. Squeeze each ring until ring ends are securely hooked together.

CAUTION: The reaction shaft support seal rings will break if overspread, or twisted. If new rings are being installed, spread them only enough for installation. Also be very sure the ring ends are securely hooked together after installation. Otherwise, the rings will either prevent pump installation, or break during installation.

4. Align and install reaction shaft support on pump body
5. Install bolts attaching reaction shaft support to pump. Tighten bolts to 20 Nm (175 inch lbs.) torque.





6. Install new pump seal with Installer Tool C-3860-A (Fig. 116). Use hammer or mallet to tap seal into place.
7. Install new O-ring on pump body Lubricate oil seal and O-ring with petroleum jelly.
8. Cover pump assembly to prevent dust entry and set aside for assembly installation.