From: John De Armond
Subject: Re: Alternator Belt Slipping - Class C
Date: Mon, 29 May 2000 23:59:36 EDT
Tom J wrote:
> In article <393322B6.858B811A@home.com>,
> John Gray <firstname.lastname@example.org> wrote:
> > My '79 GMC 400" engine has a problem with the belt for the alternator,
> > Engine & Fan belt keeps working loose. Since I am out there on the
> > at night frequently... I have to put a new belt on myself....
> > What is your secret for getting tension? I can never get the damn
> > on tight enough...
> First start with a good belt, like a Gates "cut" belt, or the same belt
> labeled for Napa, that says Gates in the corner of the label. With the
> cut belt, you see the sides of the cords in the belt instead of the
> belt being bias wrapped in fabric. Next, install the belt with proper
> tension (about 1/2 to 3/4 inch deflection in between the pullies), and
> drive for 50 or so miles. Now retension the belts and you should be
> set for a couple of years. A new belt will streach when first installed.
Excellent advice. Now some more. Observe your accessories for
vibration. if you can see an accessory vibrate, it's likely that
the bracket is flexing enough to allow the belt to slip even when
it's tensioned correctly. That was moderately common back then -
had that problem with my '79 El Camino. Ended up welding on some
carefully placed gussets. Also look at the crank pulley. My '79
came from the factory with a warped pulley. when I had it replaced
under warranty, my dealer told me that this was a common problem.
This wobbling will beat a belt (and accessory brackets) to death.
Remember that 79 was in that period where Detroit was producing pure
crap. Don't assume anything is correct without checking. I spent a
lot of time on my '79 Elky getting it to be reliable.