My alternator has been making noise for some time now. IT started with a buzz about 3-4 months ago and then kind of when to a whrrr sound. Sometimes, however, it made no noise at all. USually made noise after a lot of driving. Not is has started making awful noised and so I removed it to check things out.

I thought the source would be the bearings but before I open the thing up, I want to make sure it wouldn't be something else.

IS it possible that the bushings are just bad allowing the alterntor to move. Would this make noise similar to what I described, or should I just go ahead and replace the bearings??>

My last 240 alternator made a lot of noise for about 200,000 miles. Sold the car to a relative and it still makes a lot of noise. Our 1989 BMW 325i (similar Bosch alternator) started making noise at about 70,000 miles. Still making the same noise at 354,000 miles today. We carry a spare alternator in the trunk because you figure it has to fail eventually.

My opinion : If your alternator is still charging it's probably fine. Check the brushes for wear from time to time and replace as needed (I've never needed to, however)