Alternator and Vacuum pump Inspection Rotor Assembly Measure the slip ring outside diameter. If measuring value is without limit, replace the rotor assembly. Inspection Slip Ring Surface Condition If there is rough surface on the slip ring, use sand paper of #500 to #600 to polish the slip ring surface. Wipe away dirt on the slip ring surface by a cloth dampened with alcohol. Slip ring outside diameter: Standard: 31.7 mm (1.2480 in.) Limit: 30.7 mm (1.2087 in.) Rotor Coil Continuity Test Use a circuit tester to measure continuity between both slip rings for the rotor coil continuity. If there is not continuity, replace the rotor assembly.

Rotor Coil Insulation Test Use a circuit tester to measure continuity between the rotor coil and the rotor shaft. If there is continuity, replace the rotor assembly. Inspection Ball Bearing Inspect rear ball bearing for rotation condition. If it find not smooth rotation and/or abnormal noise on the rear ball bearing, replace the rotor assembly. aaa