I've had my Bronco for about 3 years and it eats a belt every 4-6 months. The belt isn't exactly shot, but starts sqealing so bad it's got to be replaced.

A friend told me he heard one of the pullies was out of alignment on some of them - but he didn't remember which one.

The other thing I'm wondering is the ac compressor siezed this weekend, and it burned up the belt. Then the belt snapped, or heat from the friction melted through it. Could the compressor have been "siezing" slowly for that long, with the resistance causing the squeal if it wasn't moving as freely as the other pullies?

Luckily, I wasn't far from home and was able to get the truck home before it overheated. I was also fortunate it didn't happen on the hiway or on a turn as I lost my power steering when the belt went.

Thanks,

Rick

 

I'd be willing to bet the clutch on the compressor was sticking for a while and it finally gave up on you. If the bearing was bad on the compressor pulley, it will grab the clutch intermittantly causig odd drag on the belt. While you are fixing things in that area make sure your tensioner pulley is still good and tight. If it isn't holding the belt securely the belt will slip in hard-over steering maneuvers and when the compressor kicks on.

 

I'd have to agree with Greystreak on this. I had a slight alignment on the waterpump pulley in my Bronco. It was probalby from the pulley being press fit in too far. I took a 1/2" washer, 1/8" thick and marked it for the fan clutch bolts and notched the edges to clear the bolts. I used RTV to keep the washer in place when re-installing the pulley and presto!, it lined up perfectly and never "edged" the belt again. I probably should have returned the water pump for the correctly assembled one, but this worked for me and is still on the Bronco (sold to a customer).

 

Thanks Greystreak and Tex. It seems to make sense. There were a few times recently where the power steering felt tight for a very brief moment and then it was fine again. I guess it could have been the ac clutch binding and releasing.

How do I know if I need a new compressor or just the clutch? The clutch is about $80, but the compressor is about $250.
The compressor/clutch pulley is siezed up at this point.

I guess worse case I can get a shorter serpentine hose and bypass the AC compressor so it's drivable until I can fix it.

thanks,

Rick

 

Yes, you can bypass it this way.

If the clutch will not disengage with the A/C and defroster settings turned off, then the clutch is bad. If the truck throws the belt or destroys it when the A/C or defroster is turned on but the clutch still disengages, then the compressor has seized.

 

By the sounds of this you might want to check the alignment of all your accessory pulleys. I had the same prob and it was the smog pump pulley. It turns out when they rebuild these pumps the hub that the pulley bolts to doesn't necessarily get pressed on square and is also the only pulley on the engine that goes on like that. There are two types of hub designs that I have seen, one is a round hub with with three mounting holes in it -- This is the bad design, squeels every time -- the second is a block with three legs for mounting -- This is the good one, the block is part of the shaft will not squeel.
Hope this helps.

 

I don't know that he should start replacing expensive parts all of the sudden, because this seems like a very common Bronco thing and I have heard it from a lot of people, including myself, and I don't think that they all have bad A/C clutches. There is not much on the front of my motor that has not been replaced at one time or another, and still my belt starts to chirp after a half a year or so. probably closer to a year, but it starts to chirp way before its usable service life is up. So I could keep using it as long as I didn't mind the chirp, but it starts to annoy me so I change it. It could not be easier to replace, as far as belts go; and it's not expensive enough to bother me. So I just change it and get happily(and quietly) on down the road.

If Ford trucks are that sensitive to pulley alignment that they start chirping belts after a while, I will just continue to swap the belts instead of tearing the stuff apart and swapping parts and basically guessing all the way. Everything LOOKS aligned to me, y' know? I can't fix something that does not seem broken. And if it was that much out of alignment, the belt would be noisy from day one. I am more inclined to think that, most of the time, it's the belt or the design of the belt that causes this. Not the motor. It's too common for it to be much else.

PS - I just re-read the post above mine. At least that is something concrete to look for. I will check my pulley when I change the oil, I will be doing that this week. I've never heard of that one, but I do know that my smog pump was replaced. It was replaced relatively early in the truck's life though, it may have been a warranty repair with a Ford part. I will take a look though. Anyway my problem is so minor that I don't know if I would even change the smog pump if it looks like the "bad" one.

 

I agree that the belt is prone to squeal even if everything is in good alignment pulley-wise. Its best to keep an eye on the tensioner pulley because there is a gauge stamped into the idler arm and a pair of points that designate a "normal operating range". This gauge gives some indication as to the amount of stretch the belt has undergone. The newer the belt the closer to first point the gauge reads. The older (more stretched) belt will show towards the other point. If the gauge ever reads beyond this point, the belt SHOULD be replaced.

I have also noticed, living in a very humid river valley, that belts in general, are more susceptable to squeal under humid conditions. If there is a morning mist or it has rained recently, even a brand new belt will chirp a bit until the moisture has dried off the pulleys and the belt. I chalk it off to the fact that serpentine belts us BOTH sides of the belt to drive pulleys. The smooth side has a lot less ability to grip the pulley its wrapped around. Add a little moisture and its even more difficult.

 

I do not live in a humid climate, but my belt squeaks first thing in the morning and for about the first mile of driving and then stops. That started a couple of months ago. Now, it squeaks for the first second after I start the truck, almost every time. I know the drill already, it's getting close; soon it will squeak all the time and I will have to toss another good belt.

But you did get me thinking about the tensioner itself - perhaps mine is worn a little bit, not to the point of failure but just not as good as new. That would make sense also, as the belt stretches the pulley is not holding it as well as new. Maybe I will change that thing out, as far as I know it is 15 years and 130K old. I replaced the wheel and bearing once when I thought that it was squeaking (turned out to be the alternator) but I have never done anything with the actual pulley itself. I suppose that I will change it out sometime here in the spring and see what happens.