ROD ASSEM. 7J9778 - Caterpillar

If any part of the oil pump is worn enough in order to affect the performance of the oil pump, the oil pump must be replaced.Perform the following procedures in order to inspect the oil pump. Refer to the Specifications Module, "Engine Oil Pump" topic for clearances and torques.
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Remove the engine oil pump. (1) Bolt (2) Oil pump (3) Timing case (4) Dowels (5) Inner rotor (6) Outer rotor
Remove the timing case (3). Remove the three mounting bolts (1) for the oil pump. Remove the oil pump (2) from the cylinder block.
Remove the outer rotor (6). Clean all of the parts. Look for cracks in the metal or other damage.
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Clearance of the outer rotor to the oil pump body (6) Outer rotor (7) Feeler gauge
Install the outer rotor. Measure the clearance of the outer rotor to the body.
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Clearance of the inner rotor to the outer rotor (5) Inner rotor (7) Feeler gauge
Measure the clearance of the inner rotor (5) to the outer rotor.
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End play of the rotors (7) Feeler gauge (8) Straight edge
Measure the end play of the rotor with a straight edge (8) and a feeler gauge (7).
Clean the top face of the oil pump and the face of the cylinder block. Install the oil pump and the timing case on the cylinder block. Make sure that the dowels (4) align with the holes in the cylinder block.