Did you save the old alt belts? Sounds like the new set is a wrong size.

The two-belt set is to be a matched set. That means they are like twins, cut from adjacent spots in their manufacture. I have never been happy with non-Volvo belts, ecpesially this set. Clerks in whatever parts store assure you that they match, "See - same part number and everything". Not good enough.

Another problem:
Could be worn accessory mount bushings. There are three in the alternator mount system. One is in the adjustor part that bolts to the block, the other two are in the mount bracket. When the latter two go bad, the alternator can be out of alignment and the belt difficult to adjust.


Good Luck,

Bob

:>)