Squealing fan belt driving me CRAZY
 

Three weeks ago, my brother became the proud owner of a 1930 Model A for the first time. So everything on this old car is new to us.

http://www.fordbarn.com/forum/attach...1&d=1473430961

It's a beautiful car, but we have a problem: fan belt squeal. In fact, the problem is so bad that he asked me for help.

The mystery began when we tried a new belt. The noise stopped, but the alternator stopped charging, too. In fact, it started discharging!

After 4 days of fiddling, we found that:

1) A new 1/2" belt stopped the noise, but the alternator no longer charged.

2) A new 5/8" belt charged the alternator, but the squealing was unbearable. If we thought the noise was bad at idle, when we turned on the lights and the a/c, the noise became 100 times worse.

We have tried everything:

1) New belts
2) New alternators
3) Soap
4) WD-40
5) Dressing
6) Circuit tracing

Now we are considering a mismatch of pulleys. Is that even a thing?

The crankshaft pulley looks like it was made for a 1/2" fan belt. The alternator pulley looks like it was made for a wider belt, such as 5/8".

We even made a clay/putty cast of the two pulleys to see if we could find a difference. We did. You can see it on this YouTube video:

https://www.youtube.com/watch?v=wlhYWdAN0Ak

We will appreciate any and all help about what to do next. We're running out of ideas.

Re: Squealing fan belt driving me CRAZY
 

I suspect a bad bearing in the alternator or water pump...can you turn those pulleys freely by hand with the belt disengaged?

Re: Squealing fan belt driving me CRAZY
 

Yes, we can turn the pulleys freely by hand when we pull the belts.

There's no drag on the pulleys and hardly any play.

Re: Squealing fan belt driving me CRAZY
 

IMHO you need to replace the alternator pulley with a 1/2 inch one.

Re: Squealing fan belt driving me CRAZY
 

You Stated:

A new 5/8" belt charged the alternator, but the squealing was unbearable. If we thought the noise was bad at idle, when we turned on the lights and the a/c, the noise became 100 times worse.

OK...tells me the alternator is where the problem lies because the noise is in direct proportion to the electrical load. Swap it out.

Re: Squealing fan belt driving me CRAZY
 

When I put on a leakless water pump, picked up a SQUEEL for a few days. I "think" the shaft was too long, where it hits the boss in the head???
Bill W.

Re: Squealing fan belt driving me CRAZY
 

Is by any chance the belt adjusted too loose. I don't have this problem on my A, but I have a 79 pick up and it did exactly the same thing you described when the belt was loose. Took up the slack and I could hear again.

Re: Squealing fan belt driving me CRAZY
 

As the pulley on the alternator is quite a bit smaller than the original style generator pulley, you need to install a cogged or notched belt, as it will conform much better to the smaller pulley. At driving speed of the Model A, that smaller Alternator pulley is turning at about 7000 RPM. Don't overtighten the fan belt as it will tear-up the water pump shaft and bushings in quick time.

How do I know ? Don't ask.

Re: Squealing fan belt driving me CRAZY
 

the correct belt width is a full 5/8. Some belts are 19/32, this will not work.
Also, get a cogged belt, it will go around the alternator pulley better.
It is squealing because your battery is low and the alternator is trying to work hard to re-charge the battery, and the belt is slipping.
Recharge the battery with a charger. Once the battery is full up the alternator will just be topping off the battery.
The soap you put on there is only gonna make things much worse, get rid of all traces of it. It will contaminate any new belt you put on there, get it off the other pulleys.
A good brand of a cogged belt is a Gatorback.
Sorry I do not have a PN
You may have to go on Amazon to get the belt you want

Re: Squealing fan belt driving me CRAZY
 

Put a stock generator and EVR on it.

Re: Squealing fan belt driving me CRAZY
 

We have always used a cogged belt on the alternator. We're thinking about getting an old-style V belt to see if that makes any difference.

We've tried adjusting the belt every which way.
Too tight.
Too loose.
Just right.

The only way to lose the squeal is to use the 1/2" belt. But then the alternator doesn't charge.

We get 14.1 volts with the 5/8" belt.
We get 12.2 volts with the 1/2" belt.
We get 11.7 volts with the 1/2" belt and the headlights on and the a/c on.

So I wonder if this could be the problem.

http://www.fordbarn.com/forum/attach...1&d=1473435541

There is a huge difference between the size of the "valley" for the crankcase pulley and the alternator pulley. (I just jammed plumber's putty into the pulley to get these casts.)

But I have no idea which pulley to change, or what size I would need. I don't even know how to measure a pulley. Or if this would make a difference anyway. Aren't they all the same? A pulley is just a pulley, I would think.

And I don't want to just replace parts willy-nilly. Although I probably will end up doing that.

Re: Squealing fan belt driving me CRAZY
 

Duhhhh,....the 1/2" belt is running in the root of the pulley's,..NOT ON THE
SIDES. That's why it's not charging..

Re: Squealing fan belt driving me CRAZY
 

To me that does not sound like a belt slipping, sound more like something
wrong with the alternator.

Bob

Re: Squealing fan belt driving me CRAZY
 

You mentioned "A/C" ?? Didn't see the compressor in the video.

Anyway, like others have said, the noise sounds like alternator malfunction, not belt noise. Also, the cogged belt is a must. Gates BX40 (or BX42) would be my choice in this instance.

Re: Squealing fan belt driving me CRAZY
 

An alternator with 1 bad DIODE, can sound like a bad BEARING, but that doesn't sound like your noise.
Bill Quiet

Re: Squealing fan belt driving me CRAZY
 

Re: Squealing fan belt driving me CRAZY
 

just solved the same problem, eye ball the belt from the generator side is it align with water pump and crank, I had to move the water pump shaft out just a touch to line up, it had the leakless pump with the adjustable collar with with an allen wrench. when installed it was off just a touch. take a look just for S*** and Giggles. worked for me. and all is quite on the western front.:D
good luck

Re: Squealing fan belt driving me CRAZY
 

The small 1/2" is most likely riding on the bottom of the alternator groove, so it's slipping and not spinning the alternator fast enough to make the noise. I'm wondering if you don't have a defective alternator.

Put a 4 to 6 amp battery charger on the battery for about 6 hours, then try the wide belt and see if you still get the noise.

Belts not only need to be the correct width, but the angle of the V must be correct also.

Re: Squealing fan belt driving me CRAZY
 

My terminology on this may be wrong, but Tom may be on to something here. We hope you are trying to use a belt designed for the purpose i.e. Automotive belt, not a fractional type belt that would normally be used for a different purpose, such as a furnace or other mechanical type equipment.

Re: Squealing fan belt driving me CRAZY
 

Is the crank pulley double groove as it looks like the A/C has its own belt.
Could you post a picture of the A/C side of the engine looking at the crank pulley?

Bob