Squeaky Alternator Belt - Printable Version

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+--- Thread: Squeaky Alternator Belt (/showthread.php?tid=6420)

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Squeaky Alternator Belt - pairodice - 10-31-2021

Since fixing the PennTex Alternator a year or so ago I have never heard noise from the alternator but now it squeaks when the engine first starts up and when the slide rooms go out.  I tried tightening the belts a few weeks ago and they were shredded within a 100 miles or so.  How do tight should they be?  I know there is a tool but is there an easier way to guage them?  Currently if I push on them (two belts going around the alt, engine flywheel and a/c compressor) I can push them in about 2” as I recall.  How do you guys gauge the belts please?

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RE: Squeaky Alternator Belt - Tf175 - 10-31-2021

The Detroit manual specifies 1/2 to 3/4 inch movement at midpoint of belt with firm push with thumb ( define firm push ) . Also , dual belts should be replaced as a matched set . This is from the 92 series manual , but belt drives are belt drives . 
Have you looked at pulley alignment ? It seems that if the noise started with alternator service , the alternator could be hard to rotate when loaded .
Could there be excessive current demand for some reason?

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RE: Squeaky Alternator Belt - Richard - 10-31-2021

The standard Series 60 belt setup will not handle a heavy load on the alternator without shredding the belts. Once they start to slip, they get hot, and in my experience are soon to expire. Tightening them once they have been hot never worked for very long.

Are you driving with merge switch on to charge house batteries?
Are your coach batteries down on voltage?

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RE: Squeaky Alternator Belt - bikestuff - 10-31-2021

One other thing to think about. On 653 (A CAT C12) there was a idler or tensioner pulley. It’s purpose was to apply a tension to the belt. So in reality there was no alternator adjustment.

When I got the coach, the belt would wobble all over the place. Newell could not figure it out. Fabick Cat in Joplin could not figure it out. But a very young mechanic at the Cat repair place in Birmingham spotted that idler pulley was wrong for this engine.

So…does your engine have an idler pulley? If so, it could be the idler pulley is dead?

Bill

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