1965 L79 idler pulley

[Joe L.]

Re: 1965 L79 idler pulley

Richard------


I'd like to oblige but it's too difficult for me to get at the NOS shafts I have right now.

[John F.]

Re: 1965 L79 idler pulley

Anyone know this answer?

[Page C.]

Re: 1965 L79 idler pulley

This is a NDH idler bearing GM#908076. It also has a number 88P198 on the box. The shaft OD measurement is 0.626.idler bearing 002.jpgidler bearing 004.jpg

[Mike B.]

Re: 1965 L79 idler pulley

Hi Daniel,

I replaced my original L-79 idler pulley with a repro unit way back. Thought it was the source of a squeaking noise there. Turned out to be the alternator and the noise quit after the alternator rebuild. Decided to give the original pulley a break since I bought the repro. Here's some shots of the original idler pulley from April 2nd 1965 built VIN#140XX.

You asked if there were any drawbacks to a repro pulley? Yes, there are obvious design differences with the shape of the mounting bracket. But functionally, it works fine. Dimensionally speaking it's real close so I'm still using it after installing it around 1995.

There's an original '64-'65 idler pulley for sale online right now but the seller wants $$$. If you cant find it email me and I'll give you the info if you're interested. I don't know the seller. I just stumbled on it recently before this thread of yours started. Mike

Mike's '65 L-79 Original Idler Pulley Back (1).jpgMike's '65 L-79 Original Idler Pulley Back (2).jpgMike's '65 L-79 Original Idler Pulley Back (3).jpg

[Tom L.]

Re: 1965 L79 idler pulley

I pressed out, and in the new bearing in question. I measured the shaft more than once with a "China" caliper (Accuracy?). I'd say that they were within a half of a thousandth. I did use the Locktight. Not sure if it was necessary.

[Joe L.]

Re: 1965 L79 idler pulley

Hi Daniel,

I replaced my original L-79 idler pulley with a repro unit way back. Thought it was the source of a squeaking noise there. Turned out to be the alternator and the noise quit after the alternator rebuild. Decided to give the original pulley a break since I bought the repro. Here's some shots of the original idler pulley from April 2nd 1965 built VIN#140XX.

You asked if there were any drawbacks to a repro pulley? Yes, there are obvious design differences with the shape of the mounting bracket. But functionally, it works fine. Dimensionally speaking it's real close so I'm still using it after installing it around 1995.

There's an original '64-'65 idler pulley for sale online right now but the seller wants $$$. If you cant find it email me and I'll give you the info if you're interested. I don't know the seller. I just stumbled on it recently before this thread of yours started. Mike

[ATTACH=CONFIG]99759[/ATTACH][ATTACH=CONFIG]99760[/ATTACH][ATTACH=CONFIG]99761[/ATTACH]

Mike------


The one pictured has its original bearing/shaft assembly.

[Tom L.]

Re: 1965 L79 idler pulley

Just a follow up. Installed and ran the idler yesterday, ran the engine with the A/C engaged, seemed perfect. Didn't go for a run yet, hopefully soon. Have fun!

[Richard G.]

Re: 1965 L79 idler pulley

Tom;
Even a China micrometer will do comparative measurements just fine.
Reducing the press fit by .001 on a shaft that small is significant.
The .0005 you reported seems like a small amount but is a 50% increase in the interference fit.
You did the correct thing by applying the loctite.
I did wish the size difference from stock was pointed out before I ordered the replacement.

Happy motoring.
Rick

[Daniel D.]