Cummins/Onan B43 / B48 — Oil Seal Replacement
Repair & overhaul · oil seals
For the Cummins/Onan B43 / B48, from the Cummins/Onan service manual.
Applies to: Cummins/Onan B48
Parts for this job
Part numbers from the service-parts list for Cummins/Onan B48. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Remove the bearing plate to replace the oil seal.
- Drive the oil seal out from the inside.
- Before installing seals, fill the space between lips with a multi-purpose grease.
- When installing the gear cover oil seal, tap the seal inward until it is 0.645 inch (16.4 mm) from the front of the gear cover.
- When installing the bearing plate oil seal, tap the seal into the bearing plate bore to bottom against the shoulder.
- Use a seal expander or place heavy paper around the end of the crankshaft when replacing the bearing plate to avoid damaging the seal; remove the paper once the plate is in place.
Tools required
- seal expander Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Gear cover oil seal depth 0.645 inch (16.4 mm) from front of gear cover
Full service-parts list: Cummins/Onan B48 →
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.