Cummins/Onan — Water pump (centrifugal) repair
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Procedure
- Remove water inlet fitting, drive belt pulley, cover screws, and pump cover gasket.
- Unscrew threaded impeller from pump shaft by turning counterclockwise facing impeller.
- Slide seal seat, wear face, and bellows assembly off shaft; loosen clamp screw and remove pump body.
- Remove bearing lock ring and drive shaft and bearing assembly out of pedestal.
- Replace all worn components such as bearings, seals, wear face, and impeller; use new cover gasket.
- Assembly sequence is the reverse of disassembly.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Impeller must be centered in body cover space; clearance may vary from zero to 1/16 inch
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.