HELP. Truck is still eating belts

[Dirtymaxx03]

A couple days ago i noticed that the belt on my truck was sliding off the pulley on the alternator and the belt tensioner causing it to shear. So i replaced the belt tensioner and both the idler pulleys. took the truck for a drive and the belt sheared and came all the way off. I have no idea what else could be causing this.....What do y'all think? Any help will be appreciated.

 

[ecc_33]

is everything aligned with a new belt on. sometimes the powersteering pump pulley likes to back off the shaft. install a new belt and take a look and make sure everything is aligned. If it is start it up and watch/ look at everything. see if anything is hitting the belt.

 

[Dirtymaxx03]

i watched it when i put the third belt on. everything seems fine and aligned.

 

[custom8726]

Sharp edges or burrs?? If its not alignment or idler pulleys I would have to think its something sharp cutting it Also make sure no bolts have backed out and are rubbing the belt...

 

[Dirtymaxx03]

didnt feel anything sharp. but something has to be throwing off the alignment or it wouldnt be walking off the pulleys and sheering.

 

[Bonestock]

Make sure all pulleys spin free.

 

[xcablb7]

mine is doing the same thing, i'm going to shim one corner of the tensioner it looks like its kicked in a bit