Alt. Belt size???

[m67tang]

I just replaced the v belts on my truck, all with the same size which I took off. The alt. belt size is 25-9580.

On the old belts the alternator belt would hit the vacuum pump pulley on the back side of the belt. I thought replacing it would fix it.

The new belt is so close to the same vacuum pulley it will hit as soon as it breaks in a little. there is no more room to take up slack without forcing it into the vacuum pulley.

What size belt do I need to use?
Any one else have this trouble?

thanks for the help.

 

[Jake_IN]

That seems to be pretty common thing to happen. If you search around there are a couple posts of people that put in an idler pulley between the alternator and crank pulley. Mine does it only at idle, as soon as it comes off idle it smooths out real nicely and doesn't slap at all.


Edit: Heres one link i found http://people.delphiforums.com/snotzalot/7.3idler/

 

[Compu Doc]

Your belt should be 58" from the fan to the alternator. As for the belt slapping around I would not worry about it unless the belt you put on is made by Gates. If it is a Gates belt then take it back and ask for a Dayco gold rated. I have had nothing but problems with Gates belts and have ran Dayco belts for five years before I even changed them. The Dayco gold label are rated for diesel engines. Gates does not make a belt that is rated for a diesel.

In having all the problems with Gates belts I called them about it and their response was International built the diesel motor with a vibration in it. My response to them was no ****, all diesel engines vibrate

By the way that Napa belt that you just installed is made by Gates. If it were my truck I'd replace the belt even if it is new.

 

[oldmisterbill]

I always run a 1 inch shorter belt than called for - seems to last longer and vibrate a little less. Sadly I have a new gates green belt the Mrs got me by mistake it sat awhile so I can,t return it.It looks rugged & has a green composit backing on it,so I am curious as to how it will preform. Aslo she forgot that I wanted it an inch short.We,ll see.

 

[m67tang]

Thanks for the input guys... Now I can figure out which way to go next... getting a better belt brand, to start with.