OK, here is a tough one

[Edward M.]

What is the thread size of the lower rear bolt that connects the a/c compressor to the support bracket on a 1979 Corvette?
It threads into the compressor.

[Edward J.]

Re: OK, here is a tough one

Ed, I Beleive That Most On The Bolts Were Metric 10mmx1.5

[Joe L.]

Re: OK, here is a tough one

What is the thread size of the lower rear bolt that connects the a/c compressor to the support bracket on a 1979 Corvette?
It threads into the compressor.

Ed-----


Are you referring to the LONG bolt? If so, I believe it threads into the forward, tapped lug of the bracket.

In the above case, I think that there may have been 2 different designs for 1979. VERY early may have used the 1978 configuration. For this configuration the bolt was 3/8-16 X 4-5/8". Most, if not all, 1979 used a metric bolt. It's dimensions were M10 X 1.5 X 81.5mm.

[Edward J.]

Re: OK, here is a tough one

Joe, I think the bolt Ed is talking about is the lower pivot bolt. If I remember correctly doesnt the label on compressor say the words metric somwhere to let you know the fastner type, these where the years gm didnt quite have every fastner switched over to metric sizes.those thread sizes were indicated on the head of the bolts if there were metric.

[Edward M.]

Re: OK, here is a tough one

Joe, I think the bolt Ed is talking about is the lower pivot bolt. If I remember correctly doesnt the label on compressor say the words metric somwhere to let you know the fastner type, these where the years gm didnt quite have every fastner switched over to metric sizes.those thread sizes were indicated on the head of the bolts if there were metric.

Correct, the lower rear pivot bolt. What is it?

[Edward J.]

Re: OK, here is a tough one

Ed, My Advice Is To Try A Metric Bolt And See If It Threads Into Compressor, There May Be A Possiablty That If The Compressor Was Replaced It Could Be A Std. 3/8" Coarse Threaded Bolt,not Much Else You Do If The Compressor Is Still In The Car. I Would Think The Bolt Is About 1 1/2 In. Long.

[Joe L.]

Re: OK, here is a tough one

Correct, the lower rear pivot bolt. What is it?

Ed-----


Maybe there's something I'm missing here. However, from what I understand, the pivot bolt is the long bolt that attaches the compressor to the support bracket. This is the bolt that the compressor pivots on for belt adjustment purposes. If so, it's as I described above.

[Edward J.]

Re: OK, here is a tough one

Joe, I Think The Upper Bolt Is The Adjuster Bolt(this Is The Longer Bolt, The Lower Bolt Is The Pivot Bolt At The Rear Of Compressor.(shorter Bolt)if It Is A Metric Piviot Bolt I Think Its A Recessed Head. If Its A Sae - Hexed Head.
Joe, I Doing This From Memory. There May Be One Other Bracket On The Front That Also Is Sloted For the belt Adjustment.

[Joe L.]

Re: OK, here is a tough one

Ed-----


For further clarification, attached is a photo of the compressor support bracket with what I regard as the "pivot" bolt installed. This bolt threads into a tapping on the forward lug of the bracket. There were 2 brackets used. Pre-1979 used bracket GM #364715. This bracket used a 3/8-16 tapping for the bolt. 1979+ used bracket GM #14015523 which used a M10 X 1.5 tapping. It's possible that very early 1979 may have used the 364715 bracket.

[Edward J.]

Re: OK, here is a tough one

Joe, that bracket you are showing is the lower bracket and it is a pivot bolt. The confussion is , I thought the lower bolt was shorter. meaning I did not remember the bolt going through the compressor. and it threw me of when you said it pivots on for belt for adjustment purposes. that said your never wrong Joe, everyone on this site appreciates everything you you do for its members.

[Joe L.]

Re: OK, here is a tough one

Joe, that bracket you are showing is the lower bracket and it is a pivot bolt. The confussion is , I thought the lower bolt was shorter. meaning I did not remember the bolt going through the compressor. and it threw me of when you said it pivots on for belt for adjustment purposes. that said your never wrong Joe, everyone on this site appreciates everything you you do for its members.

Edward-----

"Never wrong"? Well, I take issue with that. I'm wrong pretty often. Also, as I always advise, no one should fear being wrong here. If I did, I'd never have made a single post.

[Edward M.]

Re: OK, here is a tough one

OK, picture / 1000 word time.

The bolt I am talking about is the bolt just below the red heater hose in the first photo. Second photo is a close up.

[Joe L.]

Re: OK, here is a tough one

OK, picture / 1000 word time.

The bolt I am talking about is the bolt just below the red heater hose in the first photo. Second photo is a close up.

Ed-----


That's the bolt I was referring to. Doesn't it go through the compressor and thread into the support bracket lug on the front side?

[Edward J.]

Re: OK, here is a tough one

Ed, As Joe Said You Have Two Choices Its Either A Metric Or Sae, Thats What Appears To Be In It Now. Is The Problem The Bolts Is Not Threading Into The Bracket On The Other Side?

[Edward M.]

Re: OK, here is a tough one

Joe;

You are absolutely correct. Previous owner stuck a 2 inch long bolt in the hole and I assumed it was the correct length.

3/8 16 bolt does not thread into the bracket, so I will try the metric bolt, when I find one.

Gracias Amigo.