Factory Air Conditioning Upgrades

[rustaddict]

I have a 71 Cheyenne that I think I'm about to fix the factory Air on after years of ownership. I'm missing the compressor and hoses. I see that all they seem to offer now is the reman A6 compressor and an aftermarket one that bolts up in the factory brackets. I guess there's also the alternative of Alan Grove type brackets and the aluminum sanden type compressors. I once had a catalog that offered a kit that had an evaporator and dryer that looked like it came out if an 85ish Silverado that was designed to do away with the poa valve and expansion valve. Which is the best way to go?

[dmjlambert]

I used a kit to replace everything under the hood that holds or passes refrigerant, then restored everything in the cab myself, replacing the parts that were beyond fixing. The evaporator case had a poor attempt at professional restoration done, and I had to follow up and finish the job on that myself. I am pleased how it turned out. I would get A/C going again on another truck the same way, except I would not send the evaporator case to somebody else, I would just do that part myself. Here is my thread on the subject. https://www.67-72chevytrucks.com/vbo...d.php?t=790246

[leddzepp]

Fix what you have if it’s complete, minus the compressor. I’ve used the a12 (aftermarket upgrade that uses the factory brackets). It’s been in my truck for about 5 years now and works perfectly.

[dmjlambert]

If you end up doing away with your POA vaive, I suggest don't throw it out. They are worth money in rebuildable condition or in rebuilt and recalibrated for R12 or R134a condition.

[dmjlambert]

Here is another thread that has lots of good info and discussion about the compressor leddzepp is talking about. I had it bookmarked. http://67-72chevytrucks.com/vboard/s...d.php?t=741606

[D.B]

My 72 C20 uses the Old Air Product R134A upgrade items. I think the parts are for trucks in the 73 to late 70's. I did paint the compressor black to make it look more factory. I also added a stick-on heat barrier to the engine side of the housing to help deflect heat. Not sure if it helps but it might. My AC gets down to mid 40's. It's seems to keep the small cab area very cool in the heat of the Texas summer.

[ochremo]

Originally Posted by rustaddict

I have a 71 Cheyenne that I think I'm about to fix the factory Air on after years of ownership. I'm missing the compressor and hoses. I see that all they seem to offer now is the reman A6 compressor and an aftermarket one that bolts up in the factory brackets. I guess there's also the alternative of Alan Grove type brackets and the aluminum sanden type compressors. I once had a catalog that offered a kit that had an evaporator and dryer that looked like it came out if an 85ish Silverado that was designed to do away with the poa valve and expansion valve. Which is the best way to go?

I would check with these guys while you're deciding which way to go. They were great to deal with and really quick getting back with any questions. They have the compressor in black or aluminum. They also have the hoses already made up with crimped ends.

https://autoacsolutions.com/products...-and-tube-kit/

[howzzzit]

Buy new hoses and an A6 compressor. Easy to use the old brackets. If you're going to run R134 get the lines with the correct o rings. R12 and R134 are different because of the oil type. The new compressor should come without oil so you need to put in the correct type and amount. Some of the A6 Frigidaires were notorious for leaking at the seal. Mine did it and I read about a double lip seal that can be installed. Found an a/c shop that knew what I was talking about and they installed a seal. Been 10-15 years ago. No leaks. I'm still running R12 in my 72 C10. If all your interior parts are there it might be easier to go original. Have fun.

[71CHEVYSHORTBED402]

I had the original stuff rebuilt and finished for 134A. An Old Air 11-7201 condenser was installed into this rebuild. It fits like it's supposed to, and according to them it's suited for 134A.

I restored my evap case myself, it was in a real good way to start. If your case is clean wow this stuff does the trick. I hit it three times over three days.

[rustaddict]

Thanks for all replies. Yall have provided me with some great info and things to think about. I will come back and post my results. I am going with 134 because its easier for me to get. I'm about to buy an assembly manual in hopes that it will help me sort all the vacuum lines out.

[dmjlambert]

I like the service manual for A/C info and vacuum lines. I have a paper copy and most years are available in PDF format. http://67-72chevytrucks.com/vboard/s...d.php?t=558016

Vacuum is optional. Some people just have a manual valve they open in winter, and permanently fix the fresh air vent closed and the recirculate door open, and if you want fresh air open a window or vent a little bit. I like recirculate full time, no fresh air for me. My vacuum operated vent doors don't work quite right, I need to work on them. I'll probably just get them going and then hook them up to vacuum full time and bypass the vacuum switch.

The routing/hookup depends on whether your vacuum switch has 3 ports or 2 ports, and whether your heater water valve is open with vacuum applied or closed with vacuum applied. There are a couple different layouts.





Also the service manuals have the electric diagram. There are a couple different versions of those as well, the simpler one here from 1969 does not have an anti-dieseling relay, some years do. I doubt with modern gas anybody needs an anti-dieseling gizmo any more.

[ThreeQuarter]

I'm usually reluctant to ask questions in someone else's thread, but I think this might be info the OP would be interested in.

I'm in the middle of installing factory A/C on my '68 using parts from a '71. Looking at Classic Parts of America's website (among others), I see there are four different A/C wiring harnesses: '67, '68, '69-70, and '71-72. I'm not finding any discussions on the forum that outline the differences between them--does anyone have an overview/link for this?

[71CHEVYSHORTBED402]

Originally Posted by ThreeQuarter

I'm usually reluctant to ask questions in someone else's thread, but I think this might be info the OP would be interested in.

I'm in the middle of installing factory A/C on my '68 using parts from a '71. Looking at Classic Parts of America's website (among others), I see there are four different A/C wiring harnesses: '67, '68, '69-70, and '71-72. I'm not finding any discussions on the forum that outline the differences between them--does anyone have an overview/link for this?

If memory serves me right 71-72 had provisions for an anti-dieseling relay. I installed the following into my 71, without the relay, which I believe is a "1970 AC harness" Here's info. for that, you may find it useful.

A/C without anti-dieseling: Part #35260

[dmjlambert]

Yes, anti-dieseling relay, which I believe is a special time delay relay but don't know for sure. Other differences must be very subtle. You can use the link I gave above for PDF versions of the service manuals to find the electric diagram for each year. I already gave the 1969 version above, the only year for which there is no PDF of the Chevrolet service manual. Compare all the diagrams.

[roger0080]

Wow that AC case really cleaned up beautifully. Though your un-polished one looks pretty good compared to what we see here up in the north. Painting them does them no justice. Thanks for the tip.