Commutator Testing

1991 Mazda 626 DX, AutomaticSECTION Commutator Testing
  1. Clean surface and polish with No. 400 sandpaper if required. If surface is scored, out of round or pitted, turn commutator in a lathe.
  2. Maximum commutator runout and minimum diameter of commutator must not exceed specification after turning. See COMMUTATOR SPECIFICATIONS table.
    COMMUTATOR SPECIFICATIONS

    Application Maximum Runout In. (mm) Minimum Diameter In. (mm)
    B2200 (A/T), MX-3 V6, MX-6, Protege (A/T), RX7, 626 & 929 .004 (.10) 1.13 (28.8)
    B2600i (M/T) .002 (.05) 1.08 (27.4)
    B2600i (A/T) .002 (.05) 1.24 (31.4)
    MPV
    4-Cylinder Engine
    Standard (M/T & A/T) .004 (.10) 1.08 (27.4)
    Heavy Duty (A/T) .004 (.10) 1.24 (31.4)
    V6 Engine .004 (.10) 1.13 (28.8)
  3. Commutator mica undercut depth should be .02 -.03" (.5 -.8 mm). Minimum mica undercut depth is .008" (.20 mm). If not within specification, undercut to standard depth.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
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  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.