The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - HOW TO DO ? A/C Refrigerant Conversion??? HELP!

James McClure · 06-11-2008, 06:38 AM

Stepside:
First off, if the A/C hasen't worked in 7 years there is obviously a leak in the system which has to be located first before any repairs can be done.
Don't try and "shortcut" the repairs, it will come back to haunt you. After you have found the leak or know what it is, dis-assemble the system and replace the reciever-drier and expansion orface located at the fitting just before the evaporator in the small line. Now with the system open, flush the evaporator & condenser with carb spray or brake clean and blow out with compressed air. Use a "catch rag" and look for metal flecks. If you see them, replace the compressor, especially if it's an R4 compressor. ( big round one ) A6 compressors usually don't exhibit metal in the flush out rag. ( long compressor)[COLOR="Red"]DO NOT FLUSH THRU COMPRESSOR!!!!![COLOR="Black"] Next you'll have to get as much of the old oil out of the compressor as you can because R134 oil is different than R12 oil and they are not compatable. Next get the replacement hoses for R134. They will come with the right fittings installed. Replace EVERY "O" ring in the system. Add necessary amount of oil ( PAG oil for R134 ) directly into the suction port on the compressor and reinstall the compressor. (larger of the 2 hose ports) You NEED TO REPLACE THE HOSES!!! R134 molecule is smaller than the R12 molecule and if you use R12 hoses the 134 will leak out!!! I do believe you can get a changeover kit from GM or from LMC. A word to the wise, if you can get it from GM, get it there!! It has all the parts you'll need and directions. If you need more or a walk thru, you can call me or I'll call you. My e-mail is "jmcclur2@nycap.rr.com" I'll send you my # if you e-mail me in need of more help.

jim

06-11-2008, 06:38 AM	#2
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: HOW TO DO ? A/C Refrigerant Conversion??? HELP! Stepside: First off, if the A/C hasen't worked in 7 years there is obviously a leak in the system which has to be located first before any repairs can be done. Don't try and "shortcut" the repairs, it will come back to haunt you. After you have found the leak or know what it is, dis-assemble the system and replace the reciever-drier and expansion orface located at the fitting just before the evaporator in the small line. Now with the system open, flush the evaporator & condenser with carb spray or brake clean and blow out with compressed air. Use a "catch rag" and look for metal flecks. If you see them, replace the compressor, especially if it's an R4 compressor. ( big round one ) A6 compressors usually don't exhibit metal in the flush out rag. ( long compressor)[COLOR="Red"]DO NOT FLUSH THRU COMPRESSOR!!!!![COLOR="Black"] Next you'll have to get as much of the old oil out of the compressor as you can because R134 oil is different than R12 oil and they are not compatable. Next get the replacement hoses for R134. They will come with the right fittings installed. Replace EVERY "O" ring in the system. Add necessary amount of oil ( PAG oil for R134 ) directly into the suction port on the compressor and reinstall the compressor. (larger of the 2 hose ports) You NEED TO REPLACE THE HOSES!!! R134 molecule is smaller than the R12 molecule and if you use R12 hoses the 134 will leak out!!! I do believe you can get a changeover kit from GM or from LMC. A word to the wise, if you can get it from GM, get it there!! It has all the parts you'll need and directions. If you need more or a walk thru, you can call me or I'll call you. My e-mail is "jmcclur2@nycap.rr.com" I'll send you my # if you e-mail me in need of more help.jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.