I want to upgrade the coolant in the '77. Do I need to look at anything besides a different compressor and condensor? I was under the impression I can have some lines made to link everything to the old expansion valve/ evaporator. (Yes I plan on replacing the heater core, expansion valve, and pressure-testing the evap. I just wonder if I can use the 70's parts in conjunction with the new stuff or if I have to get a whole new system)
you MAY get by for a while..but the 134 developes more head pressure and EVENTUALLY you will break the reed valves in the comp..I would DEFINATELY upgrade the condensor ..if you can stay with r-12 the system will perform much better
I would run R12. Its what it was designed to run. I would also look into converting to a sandon compressor. Much more efficient and robs way less hp.
Check out Classic Auto Air for a Sanden conversion and R134 conversion http://www.classicautoair.com/index.htm There are a couple of drop in replacements for R12 such as R414B Hotshot and HC12a. With a R134a conversion you need to make sure you use a compatible oil and seals in the system.
I think I was misunderstood. I am replacing everything on the firewall side and I want to get a NEW compressor and condensor to upgrade, I was just wondering if I have to do anything with the firewall side stuff.
If your replacing everything in the engine compartment the only thing left should be the evaporator. No matter what freon you decide to use I would flush the evaporator out. (they make a system flush in a can) Make sure when you assemble everything to use the correct oil/freon combination.
A good resource when I was designing the air conditoning in my Mav was at this website: http://www.aircondition.com/wwwboard/ There is a lot of info on that site/messageboard about the various refrigerants available and what you need to do to convert. I decided to stay with R-12 for now.
I have changed several a/c s over to R134, both Sanden and York style compressors, never had any problems with either. Just as said, make sure to flush the system real real good, make sure all o rings are r 134 compatible, usually they are green, make sure to use the proper oil, you shouldn't have any problems. Make SURE the compressor is the one for R 134, it should say so on the box, I have bought the York style that will work with either for several big trucks, if you can't find one at your auto parts store, try a big truck parts supply store, they have them under the Truck-Air brand.
I know many of you will disagree but I going to say it any way. I have put r-134a in about 3 cars i have owned with out changing a thing or flushing out the R-12 and I have yet had a compressor go bad and I stell own one of the cars i did this to and I have had it a little over 2 years now with no problem. Now if you like to Play it safe you don't have to use r-12 or r-134a you can get you a couple of cans of Freeze-12 in which is a replacement for r-12 and you can mix it with your r-12. freeze-12 blows colder than r-134a also.
I once had an instructor who had more ac credentials and awards than I've ever seen in my life. A very impressive list in the AC world. But he says you cannot convert a car to 134a with those kits, it will not work, and if it does, it will not last. Go figure.
He may be right but all I can say is I have done it and stell have had no problems with it yet. I use to do heat and air and my boss said the same thing as your instructor did. The diff in the r-12 an r-134a is the oil that you are post to chang for the r-134a. As for the Freeze-12 it is a direc replacement for r-12 and you can mix it with r-12 it says it on the can that is what i did with my van do to it does not have dual air and I need colder air that R-134a to help cool a biger area.
I don't know about this Freez-12 but you better be careful with these so called replacements for R-12, some of them are nothing more than butane! Butane is an excellent refridgeant but is EXTREMELY flammable! Just imagine if you had a small leak somewhere, then a spark, can you say big firecracker? I'd stay with the real thing, R-12 or R-134A, no problems there.
r-12 and r-134 are the ONLY refrigerants used by mfg's..if the other stuff is that good it would be used. the propane / butane IS a good refrigerant..just NOT for mobile a/c. just wait till the hoses start comming apart internally and then you'll know. you DO not have to flush the r-12 oil to convert. as a matter of fact the mineral oil acts as a barrier to the porous hoses used in r-12 cars..you do have to get the residual r-12 out though and use ester 100 oil (4oz is plenty )
R134 is a completely different refrigerant than R134a.. Also.. you shouldn't leave the oil from an R12 system in while switching over to 134a.. The mineral oil doesnt mix with 134a like the PAG or POE oils that are supposed to be used in a 134a system.. You could most likely get away with just draining the system oil and refilling it with PAG or POE oil that's compatible with 134a... (1 to 5% of Mineral Oil in a 134a system is acceptable) The main reason, among others that it's a BAD idea (It doesn't mean that it won't work) To just recharge a R12 system with 134a is that the mineral oil won't circulate in the system like it will with 134a.. This means that your compressor will not be getting all the oil that it needs for lubrication and won't last as long as it should (but if it's already 30+ years old, who cares?). You are correct that the Mineral Oil will help seal the hoses and O rings... but you should remove the Mineral Oil by draining it.
Right! R414B Works very well without having to change any oil or anything! I've done that several times with good results! Plus you can use it either on a r12 or r134a system.. http://www.icorinternational.com/testimonial.html
