How to Change an Alternator Bearing

When a car ages, you may hear lots of little squeaks and noises as you drive, and some of these noises could be caused by the alternator bearing. It is important that you give proper attention to this because a faulty alternator will not charge your battery efficiently, and you could get stuck in the worst places with a dead battery. If you have the right tools for the project, replacing the alternator bearing is not very difficult.


  • Pullers
  • Hammer
  • Flat Head Screwdrivers
  • Socket Wrench Set
  • New Alternator Bearings and Bushing Drivers

Step 1: Preparation

Before starting the project, make sure that you take the necessary precautions first. Since you will be dealing with the alternator, an engine part that has a large affiliation with charging the battery, be sure to disconnect the battery first. This is to ensure that there is no electricity running through the system.

Step 2: Removing the Alternator Half

Locate the alternator in the engine bay. Its location will depend on the model of the car. Once you’ve found it, you will see bolts holding the two halves of the alternator together. Remove these bolts using your wrench set. There may be four or five bolts holding the two halves together. Use two screwdrivers to pry the two halves apart, eventually opening the alternator.

Step 3: Remove the Rotor

Use soft jaw pliers to hold the rotor firmly, and remove the pulley nut using the appropriate socket wrench. With this done, attach the puller to the rotor and remove it.

Step 4: Remove and Replace the Rear Bearing

With the rotor removed, you will now have access to the rear bearing. Get your puller once again and attach it to the rear alternator bearing. Turn the puller slowly until the bearing comes off the shaft of the rotor. Get your new rear bearing, and press it in. If it won’t go in, use the hammer and bushing drivers to set it in. Be careful not to damage the bearing.

Step 5: Remove Front Bearing Retainer Plate

Do this step the same way you removed the alternator half. Get your socket wrenches and remove the bolts holding the retainer plate down. Once all of them have been removed, the plate should come off freely.

Step 6: Remove and Install New Front Alternator Bearing

Now, use your hammer and brass punch to hammer out the front bearing. Do this gently so as not to damage the other parts. Next, get your new front bearing, and push it into the slot where the old bearing used to be. Again, use the hammer and bushing drivers to set it in properly. Check the bearing by trying to turn and twist the shaft to see if it is loose. Make sure that it has been driven in and secured tightly.

Step 7: Reassemble the Alternator

Put the front plate and the front pulley back in place. Return the rotor to its original place. Get the two halves of the alternator, bring them back together, and secure them by returning the bolts that hold them together. Start your car and test if the new alternator bearing still makes noises.