[mtnbktrek]

I have photos below -same belt in each photo. Why are the v grooves deeper in the front of the pulley? it is the same with crank and water pump pulleys

[mtnbktrek]

Pic 1

[mtnbktrek]

Pic2

[54nomore]

Rear pulley is for A/C belt possibly? A/C belt is usually narrower.

[mtnbktrek]

that is a 1/2'' belt in picture

one pulley is for alt the other for power steering

no a/c

[TedRamAirII]

Belts should be different width. 15 and 17 series belts. 15=15/32" 17=17/32"

[mtnbktrek]

I have never heard of different series like that

I have heard like 1/2" belt is an "a" section
5/8" is "B" section but that just tells you how much to add onto size.

Far as I know a 1/2" belt is 1/2" belt ??

[Doug]

Originally Posted by 54nomore

Rear pulley is for A/C belt possibly? A/C belt is usually narrower.

Pontiac AC belts don't cross over the water pump pulley (like Chevys do) . For Pontiacs, a single groove crank pulley is added to the double groove crank pulley on AC cars to drive the AC compressor direct.

I recently acquired a 67 Lemans with an aftermarket AC system (VINTAGE AIR). It had a Goodyear 15585 belt that squealed. The 15585 belt is a "15" Series meaning it is nominally 15/32" wide and is 58.5" long. It is a "cogged belt" (on the inside).

I looked in the installation manual and it says to use a "Series 17" belt. I changed over to a #17600 ( 17/32" x 60") externally cogged belt and cured my belt squeal.

The VINTAGE AIR installation manual for Pontiacs has a diagram picture that says to use a GM 480509 "add on" crank pulley. It is my impression that the 480509 pulley is a fairly commonly used Pontiac pulley. With their statement of saying to use a "Series 17" belt and the GM 480509 pulley, it suggests that the crank pulley on a factory equipped AC car uses a Series 17 (17/32” wide) belt, but some belt manufacturers list a Series 15 (15/32” width) belt for a factory AC car.

Pontiac pulleys……… AAARRRGGG!

[rohrt]

Yep a 15 series and 17 series is what I use too. No squeal and it works great.

[R68GTO]

I'm fighting the same issue......68 GTO with power steering and a/c. If I understand correctly, the A/C takes a 17 series, the pwr steering takes a 15 series, what about the alternator?

[rohrt]

Originally Posted by R68GTO

I'm fighting the same issue......68 GTO with power steering and a/c. If I understand correctly, the A/C takes a 17 series, the pwr steering takes a 15 series, what about the alternator?

I think its a 15 on the Alt and a 17 on the PS.

This was what I had on the bird.

[mtnbktrek]

i never knew this stuff

anybody agree what to use for alt and power steer??

[Kenth]

This may help some.

[lust4speed]

Just for clarification, Gates 7xxx series is listed as .410" wide and Gates 9xxx series is listed as .500" wide. The 9xxx series is the width called for by Pontiac, and the 7xxx series is pretty close to Pontiac wanting a 3/8" belt.

I had to use a 7xxx series with the Vintage Air Sanden compressor because of the narrow groove in the compressor. A wider belt would have rode way out of the groove. Luckily, the stock Pontiac 3rd pulley on the other end was deep enough that the belt worked good. Originally on my '67, Pontiac called for a 1/2" wide (9xxx) series belt for the compressor and the power steering unit, and a narrower belt for the alternator. Using the 7xxx and 9xxx on the water pump pulley has both belts riding exactly the same depth in the grooves.