Okay,

So I have a belt squeal that I cannot seam to find the source of, although I have run the car without any belts and the squeal has disappeared. The car is a 1971 roadrunner with a 440 six pack, and it has power steering and aftermarket A/C. I did not have this issue until I replaced the water pump and alternator along the way. The pulleys seem to be in proper alignment (by eye) and I bought a pulley alignment laser tool but it all seems to be very close. The pulleys are chrome BPE pulleys and I had no issues for the first 30,000 miles. I have even sanded the grooves. I have also replaced the harmonic balancer (verified same thickness) and still no help. Is there any trick to making this noise go away? I’m getting very desperate!

You could start by removing the belts one at a time to find the offender(s) by isolation. It is also possible that it could be a bearing squeal from a component when loaded by belt tension. Have to start isolation process somewhere. Bill

Have you tried a different brand belts?

I will take them off one at a time to eliminate the sources! And yes I have tried 3 different brands of belts and no difference!

How do the belts sit in the pulleys? The belts are suppose to be driven by the sides of the belts. Sometimes the sides of the pulleys wear away and the belt drops to the bottom of the groove, that would create a guaranteed squeal. If the belts are at the bottom of the grooves, the belt is trying to drive the pulley off the bottom of the belt and not the sides. That doesn't give the belt enough grip on the pulley. Gene

First off i agree with trying to isolate the offending accesory.
Second, you say it was fine for 30K miles. What change (s) did you make that caused the noise to appear ?

I have read that the Gates cogged type v belt has solved several squealing issues. One does have to pay close attention to the angles of the pulleys and belts as they do vary and a mismatch can drive one around the bend.
one might also try calling gates to get their input

While totally out of most everyone's budget for such a project, Gates does make a laser alignment tool that is awesome. If you know anyone who is an industrial mechanic, see if they have access to one.

Belts can be funny, to tight, they may squeal or chirp, to loose and they can and will jump or both instances can cause shredding and depositing of belt material on the pulleys, which will usually ruin them.
Somebody on here posted a great visual aid for pulley groove inspection also.

However, as one said before, it almost sounds like a beat bearing.

I agree that the lasers are awesome. A Moparts member gave me a modern one made for serpentine belts. I machined some holders for a v belt pulley and a target when I was doing my 65 Fury cop car with a Leece Neville alt. Its got a huge belt run and I had to make the alt brackets as I could not find any. This system used 2 separate idlers. Was really having trouble till I got the laser.

do you use two belts on one accessory ? if so, you need a "matched" pair, not just two of the same number.
i found this out after squeals and belt departures.

I had the problem with the "matched pair". My parts store did make good though.

Okay so I have narrowed it down to the water pump/power steering belt. I bought one of the gates laser alignment tools but it is designed for use on a serpentine system and is difficult to hold in the v groove pulleys. Any recommendations on what to do from here?

Why not just use a bore sight tool and a magnet to hold it in place?

I don’t have a bore sight tool, but I took the fan off and ran it without it and the squeal disappeared. Is it possible that the resistance from swinging a very heavy Chrysler 5 bladed fan and clutch could be the problem? Or possibly a bad fan clutch? It only squeals above 2500 rpms......🤷‍♂️

It is probably a bad fan clutch , but if you have access to a 5 or 7 blade non clutch fan and spacer to install temporarily, try it. It will replace that added weight on the water pump bearing that you removed with the clutch fan. I think you said you replaced the water pump and if so the new bearing could be noisy or the impeller improperly spaced and scraping under load. Bill

Well,
I was incorrect. The belts are still squealing (the 2 on the alternator/AC circuit and the 1 on the water pump/power steering circuit). Is there any other tool to help align these things?

Have we tried a straight edge yet?

Just a reminder, make sure the belts are not too deep down in the groove of the pulley. Some belts are more narrow then others. They should be at the top of the groove. I had a issue many years ago and found out the belt was too narrow.

I had this same problem , I used the belt tension tool and tightened to touque spec. indicated in fsm . This solved the problem

I did a similar thing but used a different approach. I like the ball bearings to center the target. How did you align / center the laser to the pulley ?

I made a pin in the center out of aluminum. I taperd it to match the pulley taper. In the aluminum I put a strong magnet. I move the pin up and down till the laser holder/target is solid then lock it in place. The laser is held to the adapter with the magnets in the laser. I made an adapter for each size pulley. The center magnet keeps it all in place on the pulley.

It does help that I have a CNC mill so its pretty easy for me to make.