Joe C, to what extent was your conversion? Also, if I just change the fittings and put in 134, other than not lasing as long as a full conversion, any substantial downside? What really is wrong with doing this and just running it until the old breaks down? This would get me up and running, buying time. Am I thinking right?

 

If the fluids gel up, it would substantially more problematic. If the hose is not barrier rated, you will need to fill it more often.

 

extent - in a nutshell, my AC system was pretty much dead in my 85. I had to replace my original compressor due to a bearing failure. along with the compressor, I replaced the accumulator/dryer, both with new ac delco service replacement parts. I used FJC's book as a guide for the whole conversion process (note, the book is not a corvette or C4, step-by-step procedure, but a generic guide on "what and why", so as with most guides, you have to read between the lines). i replaced the orifice tube with the smaller .067 assembly, and replaced the low pressure cycling switch with one set for R134a pressure. I did a thorough exterior cleaning of my condenser, including fin straightening, and cleaned debris around my evaporator. I flushed all the individual components - TWICE, including the hoses (not necessary on the compressor and dryer since they were new). finished the rebuild-conversion with new R134a compatible O-rings, and R134a service port adapters. the book spec's the amount of oil added to the system (ester vs mineral). I pulled a vacuum on the system for about 4 hours, and when it held for about 30 minutes I added the 134a - amount and pressures "by the book".

from the limited research I did on the subject, I consider it as done "correct and by the book." i'm by no means an expert on the subject, and I'm sure others will disagree on what I did or didn't do, but all I can say is, I have cold air, and haven't had issues in the three years since the conversion. it may not be the coldest air possible for the system, but it's cold enough for me, and i'm a happy camper! I went with 134a vs R12 since I was rebuilding the system, and that seemed to be the route to go at that point in time. i'm NOT sorry I did it by any means.

note - I did not change out my hoses for R134a rated assemblies. new service replacement delco's are 134a rated - I bought them, and the one's I got didn't fit for schitt - couldn't use them. I had a rather nice set from a low mileage 86, so I cleaned and installed those. while they are not 134a rated, I haven't experienced anything that's noticeable in the car's cooling. i'll probably check pressures this summer, and may (or may not) have to add Freon, but if I do, it should be minimal. I briefly had my AC on several weeks ago, and it was still pumpin' out cold air, so i'm guessing everything's still good.

as for just changing your fittings and just adding 134a - some folks around here have had success with the "$39 conversion in the can" from Walmart. short term, I guess it will work - long term - who knows? the main issues is the system's oil and O-rings. most likely, the oil mix will turn to goo, and you'll have to deal with that at some point in time. again, i'm no expert here - personally, I wouldn't do it.

 

^^^^ Couldn't agree more and the FJC kit is really nice because the book explains not only what to do but why to do it, along with relevant adjustments and measurements for conversion. It is a good product, especially for noobs.

Includes fittings and oil.