I have done quite a bit of forum searching and googling on the "Cheap" A/C conversions. None of them even mentioned junkyard conversions. I have a rig in mind to buy but the A/C doesn't work and potentially needs recharged. It is a 91 so it has R-12. Can I take all the parts from a 94 or newer from the firewall outward and bolt them right up, take it to an A/C shop and have it vacuumed and charged with 134A?

 

If you change all the parts.

 

"ALL" the parts like in the dash too? If I recall from other readings here, there are several parts that are a PITA to get to and change? If they are not that difficult to get to, please explain how. The Jeep I am looking at is a 91 with 156k and I think I can get it for 1500.

 

From what I've read the only "must change" parts, when converting from R12 to R134a are the o-rings, the compressor oil (R12 & R134a use different oil) and the high & low pressure fittings (all under the hood). I think those items can be had new for less than $25 at a auto parts store. It is a good idea but not mandatory to replace the accumulator/dryer and liquid line/orifice tube with new parts as those are both filters so old JY stuff is probably crudded up. It's also a good idea to pour a/c flush solution into the evap and cond and blow them out with compressed air. The more u replace/clean/refurbish, the better the a/c performance. As u said, have a pro pull a vacuum and add freon.

 

You asked, so here it is. If you want to put 134A in a R12 system, you can do it if you change the hoses to the new hoses. 134 will work in a R12 system, but if you want it to perform the best, then use the 134 TXV too. Then if you want that little extra efficiency out of it, then the rest of the stuff too. But the hoses are minimum or you will charge it every year and eventually it will quit cooling even with a charge in it because all the lighter constituents have bled off through the old style hoses.