Cummins/Onan 4.0 BF-1R/9500 — Generator Brush Removal and Replacement
Maintenance · AC generator brushes
For the Cummins/Onan 4.0 BF-1R/9500, from the Cummins/Onan service manual.
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Before you start
- Always replace brushes as a set and use only the correct brushes
- Never use a substitute brush
Procedure
- Remove plastic end bell screens to gain access to brushes
- Measure brush wear with a small narrow scale; replace when worn to 1 inch
- Remove and tag wires connecting to brush blocks
- Remove brush blocks and lift out of end bell
- Pull out brushes and springs from bottom of brush block
- Install new brushes with stamped BRG END side facing bearing end of generator
- Tighten brush block screws to 40-70 in-lb (4-6 ft-lb)
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Replace when worn to 1 inch
- Brush block screws 40-70 in-lb
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.