Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Bench Testing: Commutator
Inspect commutator for roughness, grooves, burns or pitting. If necessary, sand lightly with 500-600 grit sandpaper. Check commutator for out-of-round. Check mica insulators undercut. Ensure depth of undercut is .020-.031" (.50-.80 mm). Commutator may be turned a maximum of .04" (1.0 mm) from original size and mica undercut. Replace if excessively worn.
| Application | Inch (mm) |
|---|---|
| S114-486 | 1.14 (29) |
| S114-534 | 1.26 (32) |
| S114-630 | 1.54 (39) |
| S114-701B | 1.26 (32) |
| Application | Inch (mm) |
|---|---|
| M1T72088 | 1.134 (28.8) |
| M1T729857A | 1.134 (28.8) |
| M2T53883 | 1.236 (31.4) |
| M3T37783 | 1.236 (31.4) |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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