alternator belt?

Question

alternator belt snapped off while driving after i replaced the alternator with a new one... ...why is that,

i also noticed the pulley of the new one is wider than the old one by like a few centimeters and the belt was pretty thin, does that matter, it did have grooves in it for the belt..i made sure the tension was the right amount..not too lose or not too tight...but not sure what made it do this......

i bought a new belt...but what should i be doing when putting it in...?

im sure it wasnt the water pump, because it never did this, just when i replaced the alternator...

Answer 1

Assuming the replacement alternator was the correct model:

Take the pulley off the old alternator and place on the new alternator. You may need an impact wrench to remove the pulley from the alternator. The difference in pulleys should be slight, not a few centimeters. Once the alternator is reinstalled and the belt is on, check the belt to ensure that everything is in-line (i.e, the belt isn't angled forward or back, etc.)

Ran into this problem quite a bit when working at an auto parts store during college. The specified alternator would sometimes have an incorrect pulley installed. We'd just swap the old pulley for the new.

Answer 2

double check that alt. pulley. if it is wider it can throw the belt. if you still have the old one compare, if not , head for your friendly neighborhood parts store and see what thier replacement alt. looks like. if they look the same--wrong belt. also you may have a bent pulley on the rebuilt alt you bought. compare