Cummins/Onan — Disassembly (Pump 131-0257)

Repair & overhaul · Water pump 131-0257

From a Cummins/Onan service manual — check it applies to your exact model before use.

Applies to: Cummins/Onan MCCK

Procedure

1. Loosen pulley set screw and remove pulley from pump shaft.
2. Disconnect all hoses and remove pump from engine.
3. Remove impeller housing screws, impeller housing, and gasket.
4. Pull impeller out of impeller housing.
5. Remove wear plate from pump housing, using screwdriver to pry if necessary.
6. Remove external retaining ring from impeller end of water pump shaft.
7. Remove two piece seal assembly; spring portion first, second portion with screwdriver or needle-nose pliers.
8. Remove internal retaining ring from drive pulley end of pump housing.
9. Carefully drive out shaft and bearing assembly from impeller end of housing.
10. Remove slinger from water pump shaft.

Full service-parts list: Cummins/Onan MCCK →

Source: Cummins/Onan service 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.

More Cummins/Onan repair guides →