How to Fix an Alternator

Fixing the alternator in your car can be a daunting task. You must disassemble it, repair it and reassemble it after the repair. If you want to save a little money, follow these tips to help you fix an alternator.

Difficulty:

Moderately Challenging

Instructions

Disassemble the Alternator

1. Make a note of the "clock" position of the alternator. This is the front to back way it is housed in the engine. Remember it for when you re-assemble the alternator.

2. Separate the drive end frame assembly from the ring end frame by taking out the 3 thru-bolts. Leave the stator in the back housing. Remove the drive end frame from the rotor. Put the rotor in a hex wrench to remove the shaft nut.

3. Disassemble the slip ring end frame. Press out the cover pins. Take off the cover. Slice off the leads attached to the rectifier bridge terminals and take out the stator. Poke out the baffle pins and take out the baffle.

4. Take off the fasteners to lift out the brush holder, rectifier bridge and the regulator from the end frame and disconnect.

Repair and Reassemble the Alternator

1. Repair the rectifier bridge. The rectifier fails more than any other component on the alternator. Connect an ohmmeter at a low scale to heat sink from bridge terminals. Then reverse the connections. If both readings are identical, replace the rectifier bridge.

2. Clean the brush holder with a soft dry cloth unless the brushes are really damaged then replace the entire brush assembly component.

3. Spin the rotor by hand to clean the slip rings. Press a fine polishing cloth against the rings while it turns.

4. Push on outside of the bearing assesmbly to replace it. Push until it slips to the bottom of the frame. Solder the connectors back as they were originally.

5. Replace the cleaned brushes in holder and pin them in. Use some kind of electrical contact transfer grease on the end frame casting under the rectifier bridge to dissipate the heat.

6. Reassemble all the parts. Tap down on the inner and outer race of the slip ring end bearing to join both of the end frames. Replace the thru-bolts.