Scraping alternator fan on housing
 

If I tighten the bolt that holds the alternator to what I feel is the proper torque the fan scrapes on the housing. If it's loose, it dosen't scrape. New fan belt was installed, got a little worse. Could it be my alternator bearings wearing out?

Is your fan fully seated on the alternator shaft?
I replaced my fan a couple of years ago, and used a rubber mallet
all around the fan where the alternator shaft sticks through, I just kept tapping until it was perfectly seated. With the tight clearance between the fan blades and housing, it doesn't have to be off very much to cause rubbing. My fan and alternator were out of the car at the time, making it easier to seat the fan.
HTH
Craig
77 911S

I had that problem once - turned out to be a cracked pulley!

Yes, the bearing system can fail. This happened to me ('76 911S) but fortunately the brushes went first (so I got an alternator warning light) before the fan scraped. Besides the bearings, the plastic retainers holding the bearings into the alternator frame can fail (my case) - might be time for an alternator rebuild as this type of failure may also do in the alternator brushes (as in my case). Also check that all the fasteners securing the alternator to the fan shroud are intact and tight. Something is loose, missing or worn. Cheers, Jim

Before you go crazy with bearings and torque settings, read this and check your shims. I had the same problem and the article fixed my problem of shim placement.

http://www.pelicanparts.com/techarticles/911_fan_belt/911_fan_belt.htm

Sorry.

http://www.pelicanparts.com/techarticles/911_fan_belt/911_fan_belt.htm