Fan belt won't tighten

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Dogslovetrucks
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Fan belt won't tighten

Post by Dogslovetrucks »

I feel like a newbie- wait, I am a newbie. When I got my truck this summer, I replaced the belt as part of my "new owner" refresh. 2 weeks ago, I was driving at normal (low) RPM when "BOOM!"; something lets loose. Inspection revealed that the pulley half had snapped in two. I have ordered a new pulley 1/2 from SAV and am installing with a new SAV sourced belt. Now for the problem; for the life of me, I can't get the belt to tighten. I've read the manual and every post on the topic I could but I sill have 1" plus of slack. I'm not sure I'm understanding the shim process. Right now, I everything in this order from the fan (belt, pulley 1/2, 4 shims, nut). No matter how tight I take the nut, I still have wiggle in the spacers. What am I doing wrong!? Any help is appreciated!!
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Andre
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Re: Fan belt won't tighten

Post by Andre »

after you install the nut(with all 4 spacer shims on the outside of the pulley half, do you rotate the motor as you tighten? By rotating the motor while tightening, it allows the belt to "walk" to the outer most part of the pulley half, thus tightening the belt.

If you still have room to tighten and the belt is already taught, then move a shim or two to the inside of the pulley half. If you still have slack, either something is missing or you have too long of a belt.
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Dogslovetrucks
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Re: Fan belt won't tighten

Post by Dogslovetrucks »

Thanks for they reply- I have rotated the fan while tightening to no avail. Belt is an SAV (correct size)- to confirm, for maximum tightness, where should my shims be (be graphic in your explaination- I'm pretty thick).
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TechMOGogy
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Re: Fan belt won't tighten

Post by TechMOGogy »

If you need to use shims they should go on before the pulley half then the bolt
If you don't need them then remove all and just use bolt.
That is the way it is shown in my spare parts manual
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Re: Fan belt won't tighten

Post by Stekay »

If you don't need them then remove all and just use bolt.
Don't just use the bolt. The shims are moved from between the pulley halves to between the outer pulley half and bolt head (as a place to store them) as necessary to adjust the width of the pulley and therefore the the diameter of where the belt rides.
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Re: Fan belt won't tighten

Post by pinzinator »

Looking at the picture, he has the two pulley halves without shims between them, which would maximize the distance between the crankshaft and upper fan pulley. If the belt still won't tighten it is too long, try taking it to NAPA and try to get a replacement that is the next size shorter in diameter. An inch will make a big difference.
SAV's supplier could have sent the wrong belts, it does happen.
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Re: Fan belt won't tighten

Post by compunerdy »

He said the shims still move so it sounds more like the nut is not going on far enough. You might take off the nut and see if it physically can go on farther than you have been getting it to go.
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Re: Fan belt won't tighten

Post by TechMOGogy »

Stekay wrote:
If you don't need them then remove all and just use bolt.
Don't just use the bolt. The shims are moved from between the pulley halves to between the outer pulley half and bolt head (as a place to store them) as necessary to adjust the width of the pulley and therefore the the diameter of where the belt rides.
Yup I stand corrected - op manual states what Stekay said
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Re: Fan belt won't tighten

Post by milesdzyn »

I know this sounds counter intuitive but bear with me.

Since you are installing a new belt the spacer rings should be mounted on the inside of the outer V pulley half and not between the V pulley and nut.

I believe the shims are interfering with you tightening the nut down properly.

The shims go to the outside only when the V belt wears and stretches with use.

Also as stated earlier you tighten the nut down as tight as possible, then rotate the fan around a few times, retighten and repeat the steps till the nut is seated against the shims. If the V belt is too tight then remove one shim and put it to the outside and retighten the nut again. It is important that the nut is tight against the shims, there can be no play.

So if the new belt is the proper size all the shims should go to the inside, if your new belt is not metric but a close standard equivalent then one shim may have to be put to the outside.
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Andre
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Re: Fan belt won't tighten

Post by Andre »

Also, spacer washers are supposed to be keyed to match the male threads. what if one or two of the washers has a bur or is hanging on the threads instead of sliding all the way up to the pulley half.

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Dogslovetrucks
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Re: Fan belt won't tighten

Post by Dogslovetrucks »

Thanks for all the replys. Didn't get a chance to mess with it today but will do so tomorrow. Update to come- thanks again
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Re: Fan belt won't tighten

Post by Dogslovetrucks »

"And the survey says…": the replacement nut was not correctly threaded. I can thread a 1/2x20 bolt completely on the old nut, but only half way on the new. This explains how why I was full-tight on the nut but the washers still were loose. I actually have (2) new ones from SAV and both are wrong. I have a call into them to see what else they might have. Thank you again for all the replies!
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compunerdy
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Re: Fan belt won't tighten

Post by compunerdy »

That would explain it..
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Re: Fan belt won't tighten

Post by edzz »

Dogslovetrucks wrote:"And the survey says…": the replacement nut was not correctly threaded. I can thread a 1/2x20 bolt completely on the old nut, but only half way on the new. This explains how why I was full-tight on the nut but the washers still were loose. I actually have (2) new ones from SAV and both are wrong. I have a call into them to see what else they might have. Thank you again for all the replies!

1/2x20? should be m14x1,5 per spares parts manual, 1/2 x 20 isn't quite the same is it?
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Dogslovetrucks
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Re: Fan belt won't tighten

Post by Dogslovetrucks »

Not exactly (but it's as close I could find at Lowes); end result is that it threads all the way on the old one and only 1/2 way on the other :(
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