Cummins/Onan — Brush Replacement
Maintenance · generator brush block
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Procedure
- Disconnect the negative (-) battery cable at the battery terminal.
- Remove the air cleaner cover and filter element.
- Remove the brush block cover from the stator housing.
- Disconnect the F1 (+) outboard and F2 (-) inboard lead wires from the brush block.
- Remove brush block mounting screws and lift out the brush block.
- Remove brushes and brush springs; install new parts (always replace springs with brushes).
- Pull and hold both brush lead wires outward; place brush block into mounting position.
- Insert the brush retainer wire through the brush block; release the lead wires.
- Install mounting screws loosely, then remove the retainer wire.
- Adjust brush block so brushes align on slip rings; tighten mounting screws.
- Connect F1 to outboard and F2 to inboard brush leads.
- Install brush block cover, air filter element, and air cleaner cover; reconnect battery.
Specs & values
- Brush wear limit 0.425 in (11 mm)
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.