Idler Pulley?

[Perfection101]

My alternater belt broke the other day and my brother replaced it (you have to take the serpentine belt off to do so) but he forgot to tighten the idler pulley back up
On the couple block drive back to my house the serpentine belt broke, I'm guessing due to the pulley being loose. I put a new serpentine belt on and it broke the next time I drove it, it skipped off and shredded
I did the belt myself and know it was not too loose and I tightened the idler pulley as tight as I could
Is it poosible that from the idler pulley being loose the first time and moving around it messed up the bearings and that is why the belt came off again? The pulley kind of wabbles a bit but only if it is tightened all the way, if you loosen it up a bit it runs straight
I have a new pulley and belt I just don't want to keep replacing the same belt
Is there anything else it could be or does it sound like the pulley is just bad?

 

[eclipsepunx]

If the pulley wobbles I think it's safe to say that is your problem. If you have another replace it and post results.

 

[Perfection101]

That's what I thought
I just wanted to make sure first
I'll do it Thursday and let you know how it goes

Thanks