Spectacular idler pulley failure

Well, at about midnight last night the Jeep tossed its serpentine belt. This belt was maybe 8 months/10,000 (at the most) miles old. Once I pulled over, I pulled the belt out and it was pretty mangled/shredded. The g/f was impressed. Being on a rural country highway it was too dark then to see what caused it, but after work today I took a look and saw that the idler pulley (which I replaced maybe in February or March, less than 5000 miles probably) was completely destroyed.
The bearing seems fine as it still spins ok; its not seized. It's the actual metal body which got fubar'd. The way it's constructed, there's a 135 degree bend in the metal around its entire circumference from the horizontal belt surface down towards the center of the pulley. The metal at this bend is sheared (as if it was run through a can opener almost) for nearly the entire circumference, and so the flat horizontal surface is barely attached anymore to the vertical surface. That's the best I can describe it...can't get pictures up right now.
Have any of you heard of this happening? I mean, I've heard of the bearings going south and eventually seizing (which is why I replaced it a few months back) but not anything like this. It came from autozone I believe. Is it just a cheap pulley, or might there be some other explanation? I thought about serpentine belt overtension, but I used the "can it twist 90 degrees" method of tensioning and if anything that method would probably leave it a little undertensioned. In any case, it wouldn't have been wildly overtensioned, which is the only way I can imagine belt tenion being the culprit. There was no warning (that I noticed anyways). Just broke.

Any ideas?

I once had a tensioner I bought from autozone fail - the little tit that holds the thing in place sheared off in 2 months (this was on an Audi, though)

loc-tite on bolt?
it sounds as though the bolt worked itself loose and allowed the pulley to "tilt" backward-- look for abrasion on bolts or bracket behinde it.

--Shorty

may not be the problem, but you should check the harmonic balancer to make sure it is still good since the idler just died

Autozone generally means crap in my book. I'd take it back and demand a refund. Then go buy the $2 bearing and repair your original pulley.

Here's what happened to a fellow Jeeper on the trail once

Its things like this that make me cringe to think about when I go off road. (miles and miles away from people)

Almost as much as my Dana 35c.,...

Blaine- that is *exactly* what it looked like, except the speration of out from in was even more complete. I was about to bust out all my camera gear, but I couldn't do better than what you just posted. Thanks-

Do you know the origins of that pulley?

Hard to tell, but that looks like the bearing let loose?

No, I don't. It was quite old though I believe. Before that trail run he put some oil on the bearings to quiet them down. And then it let loose and sounded like a diesel until he popped the hood and discovered the carnage

okay, I actually took some pictures. The pics Blaine posted, looking at them I think I mistook part of the shredded serpentine belt for broken/sheared metal. Not sure, but at any rate here's some images for posterity:

<img src="http://www.photodump.org/stored15/P1010470.JPG">

<img src="http://www.photodump.org/stored15/P1010468.JPG">

<img src="http://www.photodump.org/stored15/P1010467.JPG">

<img src="http://www.photodump.org/stored15/P1010466.JPG">

<img src="http://www.photodump.org/stored15/P1010465.JPG">

<img src="http://www.photodump.org/stored15/P1010464.JPG">

I think this is definetly more than a bearing letting go. In fact, as I said before the bearing still spins fine by hand, smoothly and quietly. And about the bolt, I couldn't find any conspicuous abrasion. Also, the bolt was not loctite'd, but it was not loose, either. The bolt was tight and it still threads in and out easily.

Since I had already discarded the original pulley with the bad bearing, I think I'll try a dayco pulley from NAPA or Advance next. I'm not 100% sure, but I think this destroyed one from autozone was a "torq-flo". That'll teach me to buy the cheapest one...

-Rob