Cummins/Onan — Water Pump Disassembly
Repair & overhaul
From a Cummins/Onan owner's manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Care must be taken in removing the seal assembly, as the carbon seal is fragile and easily broken.
Procedure
- Remove nut and lockwasher from front of water pump shaft; pull pulley off shaft with a puller.
- Remove the three nuts mounting the shaft support to the body and remove the support assembly.
- Remove the set screw and pull or press the impeller from the shaft.
- Remove set screw from top of support and press shaft and bearings out through the front.
- Remove the seal assembly from the impeller hub; carbon seal is fragile and easily broken.
- Reassemble by reversing the disassembly procedure.
- Make sure set screw projects far enough to line up impeller on shaft; press impeller flush with shaft end.
- Pack the space between bearings with a good grade of water pump grease.
Tools required
- puller Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.