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Discussion Starter #1
68 coupe with a 289. That I have had for about a month now
Power steering no idea what kind of pump
Up graded new alternator
Electric fans
After market ac
3 groove pulley at harmonic balancer

Car make a terrible belt squeal, it is intermittent and I think it is coming from power steering. Any ideas on how to trouble shoot / fix
GC
 

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1967 Mustang Convertible
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What does your alternator look like? I noticed when I upgraded mine to the 95Amp it squealed on start up. Luckily my original alternator came with a 2 groove pulley so I put another belt and no more squeal, but I don't have any other accessory other then alternator and water pump.
 

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What does your alternator look like? I noticed when I upgraded mine to the 95Amp it squealed on start up. Luckily my original alternator came with a 2 groove pulley so I put another belt and no more squeal, but I don't have any other accessory other then alternator and water pump.
Here is a picture of alternator.
PO upgraded it when he put the electric fan on
 

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Squeals when and what makes it go away?
It’s not real specific. Does at random times. Starting to narrow it down to more when you are just putting the car under load and or starting a turn.
Normally stops when you push in the clutch and give the engine a freewheel rev

I think it had been an ongoing issue as the PO had a can of belt dressing in the trunk
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If you have a squeal when accelerating, it's generally a loose belt. Squirt some belt dressing on one pulley at a time to find out where the noise is coming from. Once in a while a belt will get glazed from slipping and the only way to fix it is to get a new belt.
 

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+1 on the loose belt. I had this problem and narrowed it down to the power steering pump belt. Tightening the belt made mine go away but I do agree on the earlier point made about belt glazing. Once you isolate the belt causing the noise and if you decide to change it, make sure the groove in the pulley is not painted while you have the belt off. This also causes belts to slip.
 

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Once I installed an electric fan and a larger alternator I had issues with belt squealing. I tried a larger diameter alternator pulley to increase belt contact surface area and help with mechanical advantage, no luck. I ended up going with CVF dual V-belt pulleys. Problem solved.

Belts can be over tightened putting stress on bearings. I was taught many years ago that one should be able to twist the installed belt so that the narrow part of the V 180 degrees so that it points outward.
 

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Once I installed an electric fan and a larger alternator I had issues with belt squealing. I tried a larger diameter alternator pulley to increase belt contact surface area and help with mechanical advantage, no luck. I ended up going with CVF dual V-belt pulleys. Problem solved.

Belts can be over tightened putting stress on bearings. I was taught many years ago that one should be able to twist the installed belt so that the narrow part of the V 180 degrees so that it points outward.
Any picture of your set up .?
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My 68, with a 289 squeals like a pig but not all the time. Sometimes at start up, sometimes when its cool outside. Like if the condensation in the air is making the belts squeal. After a while when the engine heats up it seems to go away. But boy is it embarrassing while driving sitting at a light and hitting the gas. LOL!
 

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Try going with a new belt, maybe just 1/2 inch shorter. Stock on a 289 is a trade #15405 I think. 15/32" wide, 40 and 1/2" long. How in the world I suddenly remember that after leaving the parts business 23 years ago....
 

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If you remove and replace your belts, this will give you an opportunity to spin and check each pulley that potentially might not be spinning freely. This includes your A/C clutch.
 

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For years I used Gates belts and I always had a squeak from the AC belt. Just for fun I put on a cheapo Pep Boys belt. It was very flexible and the squeak went away.
Most of the alternator suppliers will tell you that for a 95A alternator you need two pulleys or a serpentine to prevent squeaking. If you go the two pulley route you may be able to replace one of the other belts to run the second alternator pulley. If you go serpentine you'll end up with radiator fans and need another 20 amps to handle them.
 

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Discussion Starter #17
Just wanted to give an update.

Talked to the previous owner who said He always thought it was a PS issue .

So after seeing the post on the thread thought I would replace the PS belt.
New belt on out for test drive. Now squeal worse than ever.

Today pulled ac belt and ps belt and go for test drive. No notice able squeal inside as I was driving until I went to pull back into the driveway and then a small chirp. Park the car leave it running and open the hood. Electric fan kicks on and a small chirp. Does this a couple times , then I decide to give it some throttle as the fan kicks on again. Belt howles ..

Ok so now we now we only have the alternator belt on the car. I go to loosen the belt and the belt is so small That it is bottomed put in the adjuster groove. I had to take the bottom adjusting bolt out so the alternator can hang loose to get the belt off

Got a new belt that was a couple sizes bigger. This also increased the cross section of the belt as well.

New belt on go for a drive and finally problem solved.

No belt noise at all and had a blast driving around on a 65 degree winter afternoon.

So I guess the moral of the story is just because someone can get a belt on the car doesn’t mean it is the correct belt. Sometimes you just have to check other people’s work your self.

GC
 
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