serp belt keeps breaking

its a 95 cherokee country 4.0, replaced alt a/c pullie swaped fan pullies. you can see that the belt is shearding on the outer edge like its getting pulled out. Owner said balencer was replaced before. could it have walked out or replaced with the wrong part? are there any other common causes for this?

birdmanxj said:

its a 95 cherokee country 4.0, replaced alt a/c pullie swaped fan pullies. you can see that the belt is shearding on the outer edge like its getting pulled out. Owner said balencer was replaced before. could it have walked out or replaced with the wrong part? are there any other common causes for this?

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Do a visual inspection of the harmonic balancer where the weight meets the hub to see if the weight is moving off the hub.
This is definitely an indication of a balancer going bad OR possibility of the harmonic balancer bolt being loose.
Just because the balancer was replaced before doesn't mean that it can't go bad again.
Generally I either purchase the item from NAPA or the dealer when I replace parts like this.

I would guess the balancer as well, also how many miles does it have? I have a 89 and the crank shaft play is really bad the crank moves in and out and this will shred the belt as well, I am waiting for the motor to blow up and so I can replace it but she just keeps on chugging.

Sometimes the pulleys are different sizes too. I had someone put the wrong pulley on an alternator once and it was a full 1/2" out of line with the rest of the serpentine system. Check that everything is in line.

Crank pulley is probably the #1 possiblity. But if you can't find anything wrong with the crank pulley you think about this: if the power steering pump has been replaced, the pulley was likely removed and pressed back on. There is no real stop or guide on the PS pump shaft to tell you how far to press it back on, so you're supposed to measure before you remove the pulley. If whoever replaced it didn't think about that, it could be out of line with the other pulleys. You would most easily notice this by checking that the belt rides over the shiny portion of the water pump pulley.

Robs92XJ said:

Crank pulley is probably the #1 possiblity. But if you can't find anything wrong with the crank pulley you think about this: if the power steering pump has been replaced, the pulley was likely removed and pressed back on. .

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There are 6 pulleys, so there are 6 possible culprits. Could be a wobbly water pump, fan clutch etc. Get a good look at it from the side and try to see which pulley is out of line. Even a little bit will allow your belt to "creep" in or out.

I was having the same problem and my HB was not that far out, but the idler was wobbling like crazy (without screeching). Here's a pic of my HB after a month of sitting in the rain.

I have seen way too many instances of the alternator missing the rear bolt and not sitting perpendicular to the belt. The same goes for the power steering pump.

Carefully look at each pulley and make sure they are nice and square.