Cummins/Onan — Generator Brush Replacement
Repair & overhaul · Generator brush block
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Brushes will be damaged during disassembly if not held off the slip rings
Procedure
- Disconnect negative battery cable; remove air cleaner cover and element.
- Disconnect B+ (outboard) and B- (inboard) lead wires from brush block terminals.
- Remove brush block mounting screws and lift out brush block.
- Remove brushes and brush springs; replace with new parts.
- Insert stiff wire through holder base holes to hold brushes off slip rings.
- Install brush block; remove wire and center brushes on slip rings.
- Tighten mounting screws; connect B+ and B- lead wires.
- Install brush block cover and air filter element.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Always replace brush springs when installing new brushes
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.