Cummins/Onan — Oil Seal Installation
Installation · Gear cover and rear bearing plate oil seals
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MCCK
Procedure
- Remove bearing plate to replace its oil seal.
- Drive oil seal out from inside using bearing plate driver and gear cover driver.
- Before installing seals, fill space between seals with fibrous grease or stiff cup grease.
- When installing gear cover oil seal, tap seal inward until 1-1/32 inch (26.2 mm) from mounting face of cover.
- When installing bearing plate oil seal, tap seal into bearing plate bore to bottom against shoulder in plate bore.
- Use a seal expander or place a piece of shim stock around end of crankshaft when replacing bearing plate to avoid damaging seal.
- Remove shim stock as soon as plate is in place.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Gear cover oil seal depth: 1-1/32 inch (26.2 mm) from mounting face
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.