My alternator is making a loud squealing sound. Is it possible to change the bearing? The unit charges great. Thanks. Al P.

Possible, yes. You'll want an impact wrench to remove the pulley nut without mangling the pulley, a bearing puller, and likely a propane torch & plenty of P'Blaster or Kroil. Worst of it is the screws holding the case together. An impact screwdriver is your best friend here. Also the screws holding the brush pack will likely be seized. If they won't turn, drill the heads off, lift the brush pack out, and then use vise grips & heat once you've got the case apart.
-Chris

Wow! And where do I get the replacement bearing?
Thanks! Al P.

Once you've got it apart & the bearings out, take them to your local industrial park and find a bearing shop (check the yellow pages). They can match them up with an equal quality bearing for a couple of dollars.

By the way, are you certain it's a bearing? I ask because it's not at all unusual for the rubber mounts for the alternator to break down and tilt the alternator so it's misaligned with the belt. Spray a little water on the belt and see if the noise goes away... if so it's likely those bushings. Less than $2 apiece, I think, from FCP Groton.
-Chris