HOW TO DO ? A/C Refrigerant Conversion??? HELP!

[1975stepside]

I've got a 250 cubic inch straight 6, with A/C. I've seen the conversion kits at the parts stores with the new a/c refrigerant and a few fittings and such, but: Don't I have to evacuate any OLD refrigerant out of it first? Now, I have never had the A/C work in the 7 or so years I've owned the truck, but I guess it could be possible there might be a tiny bit of the old stuff inside. I'd appreciate any tips on this, many thanks!!!

[James McClure]

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

[D13]

That's great info.
How about a write-up sticky with pics?

[James McClure]

D13, I don't own any A/C equiped vehicles anymore, so pics are kind of out of the question. It would take me about a week to write up a step by step "how to do it" manual. The job only takes 3 or 4 hours IF, IF, IF, the evaporator and condenser are ok. The evaporator is a pain to change out. Your throwing the reciever and the hoses in the trash anyway, so all your left with is the flush and changing the oil in the A/C compressor. OH CRAP!!! I forgot to tell Stepside to add about 4 oz of PAG oil to the new reciever before installation in addition to either 4 oz's for the R4 or 6 oz's for the A6 compressors. After that it's just evacuate and charge her up with 134 and enjoy the cold. It all seems easy to me, I did it for 33 years, but even to the novice it's pretty simple IF you take your time and think. If you want some more tid bits of info let me know, jim

[AceX]

To convert the system to R134, you have to change the compressor, evap/dryer, and O-rings. Everything else can stay as is.

Cold as ice...

[bwright]

I've had good luck just charging up old R12 systems with Freeze12...http://www.freeze12.com/

The AC in my '92 S10 had not worked in at least 2 years. I bought a $25 Freeze 12 recharge kit on ebay (hose, 2 cans refrig, oil, gauge) and put it all in the S10's system. It worked fine and was working a year later when I sold the S10.

Your results my vary.

[impalamark]

If you system is down there is a reason it failed
first you have to find the reason before you can convert it
it you don.t have the knowledge or specialized tools
you will just end up spending money and ending up
with a system that won't work well for long
take it to someone who knows the deal
it will save you money trust me
MArk

[1975stepside]

OK, a little clarification here. The A/C didn't work when I bought the truck about 7 years ago. I have no idea if it had ever been changed over to the new stuff or not, how can I tell by looking at it? I bought it originally in California, so I assume the previous owner probably used the A/C, but as I only used it for short runs to the builder's supply etc. I just never bothered seeing about getting it recharged. For all I know, the A/C system may be in fine shape, and just need to be charged up. I just assumed, due to the age of the truck (33 years old) that it must be set up to use the old refrigerant, but it might not be, I don't know how you tell. And I don't know how many years it's been since the new refrigerant has been required.

[us111]

hello,,"usually" there is a sticker somewhere saying
it has been converted under the hood.

[impalamark]

The service valve for the refrigerants look different
theold r-12 vavle look like the valve stem on your tire when you
remove the cap
the new valves are bigger are quick dissconnect type and
usually have red and blue caps
we are not trying to give you a hard time but without basic knowledge it like trying to tell you how to rebuild a transmission
get on the internet and google pictures of theses and it can help
Mark

[Malo83]

Check this place out
http://www.autoacforum.com/