Serpentine belt issues

[Codum]

My truck has eaten two belts in three days? I replaced the factory belt two years ago at 300,000 miles just because I was fearing it would soon fail. At 360,000 miles I heard a noise under the hood, it was the belt, the rear rib was separating. I replaced it. Now at 400,000 miles Sunday it did it again, rear ribs separating. On the way home from work today, same thing rear rib separating. The tensioner seams fine, it's tight, must use 1/2 breaker bar to replace belt. All pulleys are tight, no play except on the power steer pump. The power steering pump slides 1/4" on the shaft. Is this movement the culprit, or could it be the tensioner even though the tensioner seams fine? Thanks!

[84crawling]

^x2.
Not trying to hijack your tread, I have some if the same probs.
I checked my fluids about once a week (just a habbit) and last week my belt hade jumped a back a notch and the rib hanging off had been torn off.?.? I thought the tensioner was bad, but was tight along with all the other pullys. I moved the belt back to the from of the pullys (ordered a belt) and it hasent moved since.
Did your truck eat the back of the belt?

[ttyR2]

Ribbed belts need everything lined up exactly. If the pulley on your PS pump is moving around, I'd start there.

[zrain25]

Has the powersteering pulley been taken off before I heard if it was taken of more the twice it should be replaced or something I just changed mine while I was doing a water pump. I keep the old one as a back up


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[Lunatic250]

I put in a new belt on monday cause i noticed i was missing a rib, i lined it up straight when i installed it and noticed yesterday the first rib was coming off the a/c compressor so i re-aligned it again today same S### again, all my pulleys seem to be fine and have no play except for p/s pump(which i thought was normal). Whats the best way to check if all pulleys are aligned correctly?

[blue72]

When I bought my truck it chewed one of the ribs off and wrapped it around the fan. I was able to get it home on the 7 ribs it had left. The tensioner appeared to be fine, put a new belt on... same thing. Took a closer look at the tensioner, it was bad. The tension itself was OK, it looked like the pullies were coming out of alignment when you would release the tension. So they were not strait even though they looked like it. Changed it out and 2 years later still running on the same belt. Good luck.

[Codum]

Been a little busy, but wanted to update. It was the tensioner. All looked fine as others have described above, until I looked at the alignment from over the drivers fender. The tensioner was maybe 1/4" out towards the front of truck. 66$ at advance and 10 minutes later no more issues. One bolt holds it on. I had installed the upper coolant hose that goes around the belt previously, so it was even easier to replace, just removed belt and one bolt (I think it was a 1/2"deep well and 3/8" ratchet) is all it took.

[Lunatic250]

my tensioner was shot as well. lol