Cummins/Onan — Assembly (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
- Install new slinger on water pump shaft.
- Install ceramic part of two piece seal assembly in pump housing; rubber side toward bearings.
- Coat inside of water pump housing and outside of ball bearing races with grease.
- Insert water pump shaft into pump housing and install internal retaining ring in drive pulley end.
- Install spring portion of two piece seal on pump shaft and secure with external retaining ring.
- Install wear plate so notch fits into machining in pump housing.
- Coat inside of impeller housing with grease.
- Install impeller in impeller housing by twisting clockwise while pushing into place.
- Hold gasket against pump housing, install impeller housing with four screws removed during disassembly.
- Mount pump on engine and attach hoses.
- Align pump drive pulley with crankshaft drive pulley and tighten set screw.
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.