Cummins/Onan GS-107-AC — Fitting new generator brushes
Maintenance
For the Cummins/Onan GS-107-AC, from the Cummins/Onan service manual.
Applies to: Hol-Gar GS-107-AC, Cummins/Onan J120-S/967F engine
Before you start
- Do not use emery or conductive abrasive cloth
Procedure
- Slip grade OO flint paper between contact surface and brush, flint facing brush.
- Move paper in one direction only; lift and return.
- Repeat until proper brush surface is obtained.
- Seat all brushes; new brushes may spark until seated.
- Operate generator at light load to wear brushes in.
Tools required
- Grade OO flint paper Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Collector ring brush minimum limit 3/8 inch
- Commutator brush minimum limit 3/8 inch
Full service-parts list: Hol-Gar GS-107-AC →
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.