Serpentine belts - out of style???

[jammy3]

I have gone through 3 belts in 6 months (2x checker, 1x Ford) on my '91 XLT, replaced the tensioner (complete, not just the pulley), water pump (unrelated breakage).

At this rate, I should buy these things by the case.

It seems like the belt is working it's way to the front of the truck. What I mean is that twice the belt has wrapped itself around the fan pulley and I've had 3 ribs left.

Is there some sort of alignment procedure that I missed?

Also, why does Checker offer two types / lenghts of belt based on mfg date, while Ford only offers one?

Thanks.

 

[BradE.]

Start checking pullys, one of them must be out of alignment if it keeps throwing the belt. Did you line up the mark on the tensioner to the mark on the block?

If the tensioner is new, perhaps the belts you are getting are to long?

EDIT: Make sure Ford gave you the right belt. If you X has AC the part number is JK6-876-A

Since you replaced the water pump, are you sure the water pump pully is installed correctly?

 

[boostedranger]

check your alt and ac compressor and the idler pulley(not tensioner its a seperate pully alltogether), if any of these are hanging up for any reason or the bearings in the idler are goin bad then that could cause the belt to slip out of alignment and get chewed up. Also run the engine with a good belt and visually inspect all pulleys and make sure there is no wobble in any of them when in motion(watch fingers). thats all i can think of at the moment

 

[jammy3]

Thanks for the info.

I replaced the idler pulley (the one located under the alternator) and confirmed that the belt number is correct. I then noticed that the water pump pulley is "off" a little. It looks like it's mounted to a shaft that is too short, which makes the belt come right to the edge of the pulley (the pulley is too close to the engine).

The water pump was from Napa and I returned the core already. I'm getting a junker from a salvage yard to see if they have different lenght shafts.

What could I have done wrong? I'm pretty sure that I mounted the pulley to the water pump correctly....

 

[jammy3]

So it looks like the problem is a bad water pump. The shaft is too short, so the pulley rides too close to the engine. This forces the belt off to track to the front of the vehicle and the pulley "pushes" the belt off the crankshaft pulley.

Yes, it was a rebuilt pump (from NAPA) and yes, I've learned my lession (after hearing three times yesterday to always buy a new water pump). I plead ignorance as it was the first water pump I've ever replaced.

Thanks again.