R 12 To R 134 Then Back

[icanfixall]

So if I have an R12 system that has been converted to R134 can I change it back without the hoses being leakers? I can't remember what it was about the hose leaks with 134 or R12. I need a special hose for my serpentine belt change over system and most of the ac systems in the wrecking yards are R12 systems converted to 134. I just need the low & high pressure hose because its all one piece at the pump manifold.

 

[funnyman06]

R134 is a lighter gas than R12, so the problems people had were that the R134 would leak out of an R12 system, but if it holds R134 without leaks, then it should hold R12 with out a problem.

 

[MUDKICKR]

the r134a also runs at a higher pressure. i believe where most have there problems is there a/c leaked out and since it costs so much for r12, they converted, which in turn leaked out as well. but as long as your system is leak free, you shouldnt have a problem. i believe the 134a runs about 20 to 30 psi higher pressure.

 

[nukinfuts]

Why would you want to do that? The cost to change back, Flushing the old R134 out, filling the complete system with R12 would be very expensive unless you already have the R12. Its in the neighborhood of $100 a lbs, at least 7-8 lbs would be needed..

 

[sle2115]

Why would you want to do that? The cost to change back, Flushing the old R134 out, filling the complete system with R12 would be very expensive unless you already have the R12. Its in the neighborhood of $100 a lbs, at least 7-8 lbs would be needed..

If I understand him correctly, his system has never been converted. He just needs a hose because he is converting his truck to a serpentine belt and the compressor and hose assembly is different. I'm also not sure where the 7 - 8 lbs comes from, most car/light truck systems are less than 3 lbs.

Like was said, if the hose was holding R134a, it should be fine with R12. I'd blow air through it both ways to try to get out any residual R134a oil, if it seemed to have an abundance, i'd flush it.

 

[RLDSL]

You can convert it back just fine, but you will need to run a flush through the system to remove all the R134a pag oil from the system or it will be taking up system volume and causing excessivly high head pressures to reach proper cooling. The r12 will not absorb the pag oil and circulate it, the stuff will just sit there so you need to flush it out while the system is open if you plan on converting it back to r12. Leaks won't be an issue.

 

[icanfixall]

Ok let mr try to explain better whats going on. I have a good running R12 system but... I'm changing over to the serpentine belt setup and what I'm finding in the wrecking yards is serp belt pumps with 134 running thru them. I wont be using those pumps but I wanted to use the hoses. On the srep belt pumps the low & high pressure hoese are connected with a manifold at the pumps. My current setup is differant. I will be continueing with the current R12 in my truck. I have around 45 lbs of it and the license to use or buy it. True, our trucks require around 3 lbs. I usually charge about 2 1/2 lbs and watch both low & high pressures systems. I realize there is more to charging the systems that just vacuuming and adding 3 lbs but what I do seems to work very well. I will be buying a new or rebuilt compressor because I really can't trust what I find in the wrecking yards. Really no way to tell what has been charged into those systems like Freeze12 or butane or propane... They all work very well but mixing two differant charges and NOBODY will work on your system..

 

[tknomaj]

a/c

Do You have an A/C flushing setup if so go to home depot and purchase denatured alcohol fill and flush evaporator and condenser that is what used to be used here in ca prior to big brother a new manifold assy is about 60.00 and accumulator 30.00 misc seals and orfice tube 10.00 then add oil to accumulator and charge the de natured alchol will remove all oil residue so no woory's of to much and will clean out any metal in system from prior failures. I am local and if you need any help locating this stuff pm me and i will help out P.s. compressor new 175.00 rebuilt 150.00

 

[RLDSL]

If that's the case, just flush the hoses and you're good to go

 

[lotzagoodstuff]

Ok let mr try to explain better whats going on. I have a good running R12 system but... I'm changing over to the serpentine belt setup and what I'm finding in the wrecking yards is serp belt pumps with 134 running thru them. I wont be using those pumps but I wanted to use the hoses. On the srep belt pumps the low & high pressure hoese are connected with a manifold at the pumps. My current setup is differant. I will be continueing with the current R12 in my truck. I have around 45 lbs of it and the license to use or buy it. True, our trucks require around 3 lbs. I usually charge about 2 1/2 lbs and watch both low & high pressures systems. I realize there is more to charging the systems that just vacuuming and adding 3 lbs but what I do seems to work very well. I will be buying a new or rebuilt compressor because I really can't trust what I find in the wrecking yards. Really no way to tell what has been charged into those systems like Freeze12 or butane or propane... They all work very well but mixing two differant charges and NOBODY will work on your system..

You should be just fine evaporating the system as best you can, cleaning it with something completely evaporating like alcohol, sucking it down with a vacuum pump and then filling it with the proper oil and refrigerant. To my knowledge, there's never been an issue with hoses or seals being incompatible with R12A or R134A refrigerants, but some oils can cause problems (specifically mineral oils). If you can find any new hoses that you are satisfied with shoot me a PM and I'll put you in touch with some folks who'll build you brand new hoses. In regards to the older a/c systems (when the Big 3 actually built the systems big enough to make really cold in cabin air) I would never run anything with butane or propane additives as 134A works pretty good, although not as good as R12.

 

[riphip]

Use some (not a lot) non-clorinated brake cleaner spray in the hoses & blow out with compressed air. Hook em up pull vac, shoot small amount of R12 to absorb moisture, pull real good vac & charge. The hoses shouldn't have anything but light residue since they have a liner. When the liner goes, the R134 leaks thru the rubber hose. R12 doesn't need the liner -- the R134 molecules are smaller and will leak thru regular ****** hose.

Rick

 

[opusd2]

There are some cost alternatives to R12 that HVAC companies use. They have similar properties to R12 and run at similar pressures, I've used them for very old Coolers in Very old bars with great success. A friend of mine even used one, in his R12 system and never had an issue with cooling or performance.

I will try to remember the manufactures name and brand name.

 

[BigRigTech]

Why not just have the hoses made? Lots of truck shops or A/C dealers can make hoses on site to suit your needs.

 

[RLDSL]

Why not just have the hoses made? Lots of truck shops or A/C dealers can make hoses on site to suit your needs.

That combination hose is a pain to make up. He'd still have to have an old hose assembly to re use the ends to put new rubber on it because the low side hose does a funky two sized bit on you with a real odd turn and it's pretty well impossible to make that one up with universal fittings It can be done with a seriously well stocked hose shop , but even then, most don't have the adapters for going from one size to another in a hose splice for some reason ( I've still got a handful of smaller adapters and haven't been able to find replacements ) So like I said, He'd need a used hose assembly to put new rubber on for that one. Either way he'd have to get a used hose assembly ( or buy a new one which may wind up being about the same cost if putting new rubber on by the time you total it up)

 

[david85]

I use duracool in my AC system. Works well and is dirt cheap. I heard it may be illegal in some states though.