Changing A/C back to R12 from 134A on my 71 - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jimfulco · 05-30-2003, 05:29 AM

Which one is synthetic? PAG or POE or???

Andy4639 · 05-30-2003, 07:05 AM

I changed mine out about 4years ago are longer. Go to the local junk yard and buy the complete system out of a later model truck (73 and above) take old system out and retro fit everything back in. I did this and on 85 degree days mine runs at 38 t0 40 degree's and has never over heated. I also have it hooked up to cycle the compressor on and off and it works great.
Here are some pictures of the set up, look at the difference it makes to the fender well as well.

The reason I say get from a junk yard, is you have all the peices that you need for that year truck, and then you can go buy all the new stuff that you will need.
I only payed $35.00 for the complete system and pulled it myself. I bought a old model compressor ready for R134-A.

Andy4639 · 05-30-2003, 07:11 AM

I also hooked the hoses up without changing anything on them as you can see in the picture. I had to curve them around, but the connections worked with both systems. I took the old dryer out of the system also because of it being one of the weak points of the older system.

Gene · 05-30-2003, 11:16 AM

So one last time before I have this done, I am putting a new compressor because my old one locked up, but do I need to change the dryer? It is still pretty new because they put it on when they did the conversion. Can I use the old hoses and everything else when I go back to r12? Is there a cheaper suitable replacement that I could use instead of R12?

Could my compressor have locked up because os something the mechanic did wrong? I read earlier that someone used alcohol to clean the system and it caused the compressor to lock up.

Chevy Wrench · 05-30-2003, 03:00 PM

Yes, I would say the mechanic did do something wrong to make the compressor lock up. You need to replace the receiver/ drier, compressor, all o-rings, orfice tubes or expansion valves, and any hose that has a muffler on it. You will also need to flush and back flush the entire system. ie; hoses, condenser, evap. core, etc... R-12 is more volitole than r-134a, so the seals and o-rings will need to be replaced. We use a substitute for r-12 called Enviro- Safe. It is compatible with both systems, and safe for the environment. Plus a lot cheaper than r-12. Good luck.
John
The reason you need to change the drier is because since you locked up your compressor, there are tiny pieces of metal floating around inside your a/c system. You cannot get it all out of the drier, therefore requiring relpacement.

Gene · 05-30-2003, 03:16 PM

Thanks chevy wrench, that helps me tremendously.

Chevy Wrench · 05-30-2003, 06:25 PM

No problem, anytime you guys need help with a/c, just ask. Afterall, thats why we are here. Right?

05-30-2003, 07:05 AM	#27
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	A/C conversion I changed mine out about 4years ago are longer. Go to the local junk yard and buy the complete system out of a later model truck (73 and above) take old system out and retro fit everything back in. I did this and on 85 degree days mine runs at 38 t0 40 degree's and has never over heated. I also have it hooked up to cycle the compressor on and off and it works great. Here are some pictures of the set up, look at the difference it makes to the fender well as well. The reason I say get from a junk yard, is you have all the peices that you need for that year truck, and then you can go buy all the new stuff that you will need. I only payed $35.00 for the complete system and pulled it myself. I bought a old model compressor ready for R134-A. Attached Images __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

05-30-2003, 07:11 AM	#28
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Another I also hooked the hoses up without changing anything on them as you can see in the picture. I had to curve them around, but the connections worked with both systems. I took the old dryer out of the system also because of it being one of the weak points of the older system. Attached Images __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

05-30-2003, 11:16 AM	#29
Gene Registered User Join Date: Aug 2002 Location: Muskogee, Oklahoma Posts: 2,914	So one last time before I have this done, I am putting a new compressor because my old one locked up, but do I need to change the dryer? It is still pretty new because they put it on when they did the conversion. Can I use the old hoses and everything else when I go back to r12? Is there a cheaper suitable replacement that I could use instead of R12? Could my compressor have locked up because os something the mechanic did wrong? I read earlier that someone used alcohol to clean the system and it caused the compressor to lock up. __________________ 1971 SWB 4X4 Build BOARD MEMBER #5448 BOOMER SOONER!!!!

05-30-2003, 03:00 PM	#30
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	Yes, I would say the mechanic did do something wrong to make the compressor lock up. You need to replace the receiver/ drier, compressor, all o-rings, orfice tubes or expansion valves, and any hose that has a muffler on it. You will also need to flush and back flush the entire system. ie; hoses, condenser, evap. core, etc... R-12 is more volitole than r-134a, so the seals and o-rings will need to be replaced. We use a substitute for r-12 called Enviro- Safe. It is compatible with both systems, and safe for the environment. Plus a lot cheaper than r-12. Good luck. John The reason you need to change the drier is because since you locked up your compressor, there are tiny pieces of metal floating around inside your a/c system. You cannot get it all out of the drier, therefore requiring relpacement. __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const. Last edited by Chevy Wrench; 05-30-2003 at 03:04 PM.

05-30-2003, 03:16 PM	#31
Gene Registered User Join Date: Aug 2002 Location: Muskogee, Oklahoma Posts: 2,914	Thanks chevy wrench, that helps me tremendously. __________________ 1971 SWB 4X4 Build BOARD MEMBER #5448 BOOMER SOONER!!!!

05-30-2003, 05:29 AM	#26
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Which one is synthetic? PAG or POE or???

05-30-2003, 06:25 PM	#32
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	No problem, anytime you guys need help with a/c, just ask. Afterall, thats why we are here. Right? __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.



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