V-belt problem on '95 940

I have on-going issue with my alternator belt loosening over time and
eventually breaking. Yesterday, it broke for the fourth or fifth time, and
resulted in a tow home. I don't know what I'm doing wrong installing them.
Seems straightforward enough and the belts seem okay a first for a few
months, but they eventually loosen, start squealing, and finally break. I
never seen this happen on any of my other vehicles. I first noticed this
problem when I first bought the car two years ago. The belt was loose and
flopping around when at idle. I had the owner tighten it before I bought it
and drove it home. That was a *several* belts ago!

I must be missing something.

Anyone have some insight to this?

 

check the bushings...the unit may be "out of
alignment" w/the other pully...causing friction...