FL-356C

Did a search and found nothing on this. Not long ago as I had to replace my gen belt. A few days later as I noticed a grinding noise as I was backing out of the garage. It was a broken rear pulley half. Went ahead and ordered both halves and replaced. I needed to remove some shims with the new belt, but it looked like I was set. Then yesterday after a drive I peeked back there to check on it, and had another broken rear pulley??? What am I doing to break these?

Steve Jensen

Do you have a total of 10 shims? Either between back pulley and generator or between the halves. But you need a minimum of 10 total...

jcnesq

+1 - you need them all!

hoffman912

i second that, you need all 10 shims. also, it is key to replace the hub as well as the pully halves, especially if they are breaking on you.

Steve Jensen

FWIW the 10 total shims are required so the big nut actually tightens against the pulley instead of bottoming out. If the big nut bottoms out, then the wobble ensues and Bad Things happen...

troos

I agree with everyone about the importance of using all 10 shims. This is not, however, the only issue here. A too tight belt puts too much tension on the pulleys and can break them. Loose belts save pulleys! As long as it doesn't slip or screech, it's probably tight enough. I like to have about an inch of play when I lightly press the belt from the side.

FL-356C

Thanks for the responses. So by moving some shims from front to back adjusts the tension correct? Also, I assume that the nut needs to be tightened all the way?

BTW, when I pulled the first rear broken pulley (which has been on the car for the last 10 years at least) it was not the same as the new one. The new one had a rectangular hole just as the front. The old one was round with a notch sticking out to secure it against the hub. I just assumed someone had put a VW pulley or something on there at one time? The new belt was ordered from Stoddard so I assume it is correct?

Steve Jensen

Belt tension is taken care of by the number of shims between the halves. More shims = wider gap = looser belt. And yes, the nut needs to be tightened all the way, but you need to make sure it isn't bottoming out...

FL-356C

Thanks Steve. Educate me on "bottoming out".

jayster

Your belt tension was too high. Check your owners manual or Elfrinks guide. Hell even the idiots guide to VW's covers it pretty well. Bottoming out, nut is tight but not clamping the shives ( halves ) together. too tight a belt causes flexing in the shive, and will crack from the stresses. New hub, halves, shims and maybe a nut is in order.