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Unread 06-10-2013, 07:20 PM   #1
LeePrather
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Fan belt

My cj has been sitting around a week and now I try to crank and the new fan belt won't turn. I can turn it by hand and it squealed before, but turned. Any ideas? I checked and my pulleys are turning, but it's like it isn't gripping the belt? I have loosened the alt all the way out and tightened it all the way down with no change?

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Unread 06-10-2013, 11:35 PM   #2
wrongway92407
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if it''''s adjusted out all the way them the belt is to long. How much slack do you have in the belt
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Unread 06-10-2013, 11:39 PM   #3
LumpyGrits
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There's adjustment also in the PS pump. IF you have PS.
LG
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Unread 06-10-2013, 11:44 PM   #4
BagusJeep
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It may be a narrow belt.

With a Vee belt the grip is on the side of the belt, the flat underbelly is not supposed to be in contact with the pulleys.

In normal use with low tension the sides can slip on the pulley, maybe giving a side squeal, and you will get lower levels of power transfer to the ancillaries. Correcting the tension will make it all work again for the life of the belt.

With wear the rubber on the sides of a standard belt is worn down, often leaving a ridge at the top of each side. The underbelly then contacts the inside of the pulley, does not grip it as well as the sides did, and you get the underbelly squeal. You could conceivably have the same if the new elt was an odd profile. The squeal is because it is slipping over the pulley and increasing the tension will have only a short term effect, eventually it will squeal again. It is quite possible that no matter how much tension you put on it the slippage will continue.

If it does not move at all you may have a pulley or ancillary that is not freely turning and is wearing the belt. You need to take the belt off and have a look at each one again.

To check the belt just look at it and compare it to the profile of the pulleys. If you have signs the underbelly is contacting the pulley it is not going to work.

Why did you change the belt? Did you work out if it was at the end of its service life or there was something else wearing it down?
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Unread 06-11-2013, 12:16 AM   #5
LeePrather
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Quote:
Originally Posted by wrongway92407
if it''''s adjusted out all the way them the belt is to long. How much slack do you have in the belt
I adjusted my alt pulley to loosen because it seemed super tight. There was no play in it. Before I made it super tight it had a 1/2" play max, but I was concerned about rubbing on a bracket.
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Unread 06-11-2013, 12:16 AM   #6
LeePrather
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Quote:
Originally Posted by LumpyGrits
There's adjustment also in the PS pump. IF you have PS.
LG
No ps pump (yet)!
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Unread 06-11-2013, 12:21 AM   #7
LeePrather
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Quote:
Originally Posted by BagusJeep
It may be a narrow belt.

With a Vee belt the grip is on the side of the belt, the flat underbelly is not supposed to be in contact with the pulleys.

In normal use with low tension the sides can slip on the pulley, maybe giving a side squeal, and you will get lower levels of power transfer to the ancillaries. Correcting the tension will make it all work again for the life of the belt.

With wear the rubber on the sides of a standard belt is worn down, often leaving a ridge at the top of each side. The underbelly then contacts the inside of the pulley, does not grip it as well as the sides did, and you get the underbelly squeal. You could conceivably have the same if the new elt was an odd profile. The squeal is because it is slipping over the pulley and increasing the tension will have only a short term effect, eventually it will squeal again. It is quite possible that no matter how much tension you put on it the slippage will continue.

If it does not move at all you may have a pulley or ancillary that is not freely turning and is wearing the belt. You need to take the belt off and have a look at each one again.

To check the belt just look at it and compare it to the profile of the pulleys. If you have signs the underbelly is contacting the pulley it is not going to work.

Why did you change the belt? Did you work out if it was at the end of its service life or there was something else wearing it down?
You have an angle I didn't consider. I put an aftermarket ac in and changed around the alt location and added the ac compressor. It came with a new belt that would drive my 4 points size wise. I hadn't considered width. I had all this in last week and it pulled and turned, but it squealed bad. I've had the jeep apart and not driving for a week now and it isn't pulling at all. Looking at my original, it does seem like there is a noticeable difference in width. Gonna try something different tomorrow. Thanks for the replies all!!
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Unread 06-11-2013, 12:42 AM   #8
BagusJeep
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Last question, did you get all the new and old pulleys lined up? Even changing an alternator I sometimes have to shim it back and forth with washers to get the alignment spot on.
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1981 J20 258ci - Gladys
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Unread 06-11-2013, 12:50 AM   #9
LeePrather
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Quote:
Originally Posted by BagusJeep
Last question, did you get all the new and old pulleys lined up? Even changing an alternator I sometimes have to shim it back and forth with washers to get the alignment spot on.
I did shim it back a quarter inch and it seems like it's level with the other pulleys, but I've been looking hard at the angle of the bracket which might have the compressor higher on the front than the back. The squealing seemed to be coming from the alt though which makes me think width is the most likely culprit.
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Unread 06-12-2013, 08:00 AM   #10
LeePrather
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Wider belt fixed the problem. Thanks for the help!
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