Skip to main content
Alternator Overhaul


Exploded View
Special Tools Required

Driver handle, 15 x 135L
 07749-0010000

Bearing driver attachment, 42 x 47 mm
 07746-0010300
NOTE: Refer to the Exploded View as needed during this procedure.
Alternator Disassembly
  1. Remove the four through bolts.

  1. Heat the rear bearing seat with a heat gun for about 5 minutes (50−60 °C, 129−140 °F).

  1. Separate the rear housing from the drive end housing by inserting a flat-tip screwdriver into the openings and prying them apart.
    NOTE: Be careful not to damage the stator with the tip of the screwdriver.

  1. Separate the rear housing (A) and drive end housing (B) with the stator (C) attached to the rear housing.

  1. If you are not replacing the front bearing and/or rear bearing, go to Step 15 . Clamp the rotor in a soft-jawed vise, then remove the pulley locknut.

  1. Remove the rotor.
  1. Inspect the rotor shaft for scoring, and inspect the bearing journal surface in the drive end housing for seizure marks.
    • If either the rotor or drive end housing is damaged, replace the alternator.
    • If both the rotor and the drive end housing are OK, go to Step 10 .

  1. Remove the rear bearing using the puller as shown.

  1. Use a hand press to install the new rear bearing. Apply pressure only on the inner race to avoid damaging the bearing.

  1. Remove the front bearing retainer plate.

  1. Support the drive end housing in a vise, and drive out the front bearing with a brass drift and hammer.

  1. With a hammer and the special tools, install a new front bearing in the drive end housing.

  1. Remove the stator.

  1. Remove the terminal insulator (A) and harness bracket (B).

  1. Remove the voltage regulator/brush holder assembly (A) and the rectifier (B).

  1. Check for continuity in each direction, between the B terminal (A) and P terminals (B), and between the E terminal (C) and P terminals (B) of each diode pair. All diodes should have continuity in only one direction. Because the rectifier diodes are designed to allow current to pass in one direction, and the rectifier is made up of six diodes (six pairs), you must test each diode in both directions for continuity with an ohmmeter that has diode checking capability: a total of 24 checks.
    • If any diode failed, replace the rectifier assembly. (Diodes are not available separately.)
    • If all the diodes are OK, go to Step 19 .
Stator side
Rear housing side

Alternator Brush Inspection
  1. Measure the length of both brushes with a vernier caliper.
    • If either brush is shorter than the service limit, replace the rear housing assembly.
    • If brush length is OK, go to Step 20 .
    Alternator Brush Length
    Standard (New):
    23 mm (0.91 in.)
    Service Limit:
    18 mm (0.71 in.)


  1. Unsolder the brush leads from the voltage regulator/brush holder assembly with a 100 W soldering iron (A), then replace the brushes.

Rotor Slip Ring Test
  1. Check for continuity between the slip rings (A).
    • If there is continuity, go to Step 22 .
    • If there is no continuity, replace the rotor assembly.
  1. Check for continuity between each slip ring (A) and the rotor (B) and the rotor shaft (C).
    • If there is no continuity, replace the rear housing assembly, go to Step 23 .
    • If there is continuity, replace the rotor assembly.

Stator Test
  1. Check that there is continuity between each leads (A).
    • If there is continuity, go to Step 24 .
    • If there is no continuity, replace the stator.
  1. Check for continuity between each lead and the coil core (B).
    • If there is no continuity, go to Step 25 .
    • If there is continuity, replace the stator.

Alternator Reassembly
  1. If you removed the pulley, put the rotor in the drive end housing, then tighten its locknut to 110 N·m (11.2 kgf·m, 81.0 lbf·ft).
  1. Remove any grease or any oil from the slip rings.
  1. Install the voltage regulator/brush holder assembly and rectifier on the rear housing.
  1. Install the stator on the rear housing.
  1. Push the brushes (A) in, then insert a pin or drill bit (B) (about 1.8 mm (0.07 in.) diameter) to hold them there.
  1. Heat the rear bearing seat with a heat gun for about 5 minutes (50−60 °C, 129−140 °F).

  1. Put the rear housing assembly (A) and drive end housing/rotor assembly (B) together, tighten the four through bolts (C).

  1. Pull put the pin.
  1. After assembling the alternator, turn the pulley by hand to make sure the rotor turns smoothly and without noise.