This is a fairly easy conversion, assuming that you have all the proper tools. You won't like the result though. R134a doesn't cool worth a damn in R12 systems. I am almost ready to drive my Suburban down to Mexico and get it converted back.
Earle
I did the conversion in my 83 Wagoneer Limited. First you should NOT do it if the R12 is still running well, ie no leaking. If you have to convert, then you'll need to vacuum out the rest of the R12 left in the system. You might have to change the evaporator/condenser as well. After you vacuum it out, check for leaks with a Freon dye. After that you should be able to pump the R134a in. But as Earle pointed out, don't expect it to perform like the R12 did. R134a takes longer to cool, and it won't cool as much as the R12 did. Hope that helps.
IT is worth taking the vehicle to a local a/c/ shop for the conversion. I had this done in a maxima with excellent results. Tools and procedures are the key. Must admit I never tried this in a Jeep, tho. Good luck. Bob
Earle
When your conversion was done, it may not have been done properly. I'm lucky to have a best friend who does A/C conversions in his business, and when he did my conversion, I didn't notice any decrease in cooling. I'm a dummy when it comes to A/C, but he said something about a variable orifice valve or tube that he changes when he does the conversion. Apparently this makes quite a difference because my air is colder than I need. I'll try to get more details about it to see if it is something that is common for all A/C systems.
Chris
I already installed the proper variable orifice valve...
Earle
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Well that shot my theory in the foot, didn't it? ;)
Chris
The 134a will normally cause a 10% (more or less) decrease in cooling capacity.
EXTREMELY IMPORTANT......thoroughly flush the old oil out of the system, and make sure there is NO R12 left.
R12 is very antagonistic to R134a compatible oils and can cause a sludge build up that will kill the compressor. (depending on how much, etc.)
DJR
more better to fill by weight - especially w/R134A
Agreed, but you can get close with number of cans. If he is using the same size cans that I do, five cans is three pounds, twelve ounces.
Earle
here's a link that you might find interesting. it's worth a look
I converted and the r134-A cools just fine.
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