AC R-12 to R134a retrofitting

[MoparGLH]

Hi, everyone
I'm looking to retrofit the A/C system on my 86 GLH and was just wondering what are the procedures and what is the best kit to buy because summer is upon us and since this is my daily driver for now,I really don't feel like roasting this summer.I want to make sure I do it right because I dont want to damage my car,and more importantly hurt myself.Thanks

[mmtphoto]

I have done a few and you need to get the high/low fittings for the access ports and screw them on top of the old r12's then evacuate the r12 (the enviornmental disclaimers go here)-you need to then have some sort of vacuum pump to get it down to 29 inches vacuum,this takes about 20 minutes to 1/2 hour- then fill it with r134-

I don't remember how much but I think it was something like 24 oz or less-R134 gages should be used, they dont cost alot and i think readings are supposed to be around 40 for low and 150-200 for high-it has been a while since I did a few cars that I have, so my memory is a little fuzzy on exact details, but it is not difficult. If done properly, it does get the temps at the vents on the dash around 40 degrees-not as cold as r12, but plenty cold for ac. If you don't do gauges, there is a sight glass that shold run free of bubbles when full. Others will chime in but I hope this helps.

[MoparGLH]

Ok,I see 2 ports.One is on the compressor itself,and and one is on a hose routed to the firewall.Is the one port on the hose the low port and the one on the compressor the high port?

[mmtphoto]

the larger one is the high pressure (not on the compressor) and the lower is on the compressor-that is where you fill the system-while you are at it, it is not a bad idea to get a small can of oil so that it lubes internal parts

[genghis05]

Ideally after vacuuming out the r12, you crack open a line and pour out (into some container for disposal, just assume I state the proper enviro stuff) the old oil. the oil used with r12 doesn't like r134 and will be a sad panda. I think it hardens or something, its been awhile since the class. as long as you get enough r134 oil in there its ok, our teacher said when putting it in, err on the side of excess. I did a 70's model pickup this way and the old brick gets pretty cold. something to be said for a 100+lb compressor pump I guess.

[jrbisig]

The best way, remove the r12, replace the compressor and accumalator, flush the evap and condensor to get rid of the r12 oil. How 99.9% do it, take the compressor off the car, dump all the oil out of it. Put in about 2 ounces of r134 oil. If the accumalator is cheap, I would put one on. Put 2 ounces of oil in the acc. Remember that the two oils do not like each other and after time will degrade whatever they touch(where not talking 6 months here On a good day, 84 degrees, 60% humidity, your low side pressure should be around 24 to 28 psi, and the high should be 150-225(this depends a lot on how much air is moving over the condensor).
james

[MoparGLH]

Ok,thanks,everyone.Ive been reading that I need a new dryer?And also,does the compressor only engage if there is refrigerant in it,or can it engage when it is empty?Because I switched it on and I didnt see or hear it engage.Will I need a new compressor also?

[NAJ]

The system gets filled to 80% of R-12 Capicity when changing over to R-134A.
Do not trust the sight glass on the drier, R-134A may always exhibit small bubbles in the sight glass. Do not overfill,R-134A is more sensitive than R-12 and the pressures run higher.
Be sure the cooling system is functioning properly, the front of the car (in front of condenser) is free of debris and all lower air deflectors(if equipped) are in place.

[4Daytonas]

Auto parts places have conversion kits that have everything you need except a dryer(you should get a new one).Use only Ester oil such as Castrol Retro fit oil.Don't use PAG.Also flush system with a cleaner for that purpose.At least the condenser.the Ester will blend with leftover r12 oil.Everyone has given good advice-I only wonder about"r134oil".DO NOT use PAG.

[mmtphoto]

you can force the clutch to turn the compressor by jumping the wires on the schrader valve (spelling is probably not right)-it is a large looking deal with two wires near the firewall (high up)-if you do jump these wires and force the clutch to turn the compressor, I would not do that for very long without oil or r134 in the system, it is not good for it-

Actually, I have only jumped mine to be certain that my system/clutch/compressor is functioning prior to going to town evacuating, filling they system. let us know how you make out-by the way, I have used the sight glass as a 'rule of thumb' on the dryer to fill mine, it is NOT as good as using gauges-others on here have done this more recently than I have, I actually did conversions in the early-mid nineties so my memory and probably the procedures I used were somewhat experimental since it was all kind of new then-but my 88 shelby still is blowing cold. I did not have any problems with it blowing cold when I changed mine over, it was just getting hard to get r12 then, so i changed it-i did use a good pump after i get rid of the R12 (enviornmental disclaimer inserted here) and I did put in non-pag, whatever it was called for in a 134 changeover-I didn't remove the compressor, I didn't replace anything-still works, I have, I think hit it with a can of 134a maybe once or twice in the last 10 years, and I did replace the clutch once-5 years ago? Face it, you can't find r12 anymore (if you can you have to mortgage the house) and if you have a working AC system, this does work.

[MoparGLH]

Ok, a little update.I bought this kit from Autozone from Quest for 38 bucks.It comes with 3 cans of R134a ,2 retro fittings ,1 for the high,and 1 for the low port and and a hose with a gauge on it.the refrigerant has oil in it already.I had my friend at a shop evacuate the system(Although it was empty) and I I put the retro fittings on and plugged in the hose with the gauge and can of refrigerant and it was funny because as I was filling it with the R134a,I had the car running with the AC on and when the compressor kicked on,it startled me and I jumped away from the car,LOL(I thought it was going to blow!) but after seeing it was ok,I went inside the car and wow!COLD AIR was blowing.I only put in 2 of the 12oz cans of R134a and the the gauge read 30LBS of pressure.I still have one extra can left so I'm wondering if I should go ahead and put that can in too,or maybe just save it.Well,hopefully it stays working.Thinks alot for everyones help.And just to be safe,I did have the AC system flushed.

Thanks Again,Guys!!

[mmtphoto]

if you have any kind of thermometer, it should read about38-40 degrees if fully charged, you should drive it around a little to get air through the front so that it works like it should, or you can use a hose to cool the condenser in front of the radiator-the gauge is the best though, i doubt you need to add any more-you don't want to overfilil, better to leave it a little low and add later if needed (like if it cycles alot)-when your friend evacuated the system, did he use a pump to draw it down to -29hg?it takes a while to get it there,
(20 plus minutes) then you fill it-when the pressure gets high enough, the clutch will cut on to drive the compressor. sounds like you got it, I heard it's going to be almost 95 degrees here later this week-enjoy.

[crusty shadow]

ideally you should have around 40-45 psi on the low pressure side with the compressor running. do NOT overcharge the system- will just make all your seals leak and your compressor will wear out faster.
some of the comments i saw above were apalling!!!
R-12 is an ozone depleting flourocarbon. do NOT under any circumstances release it into the air! if you do and the EPA finds out, $10,000 fine, no ifs ands or buts!
also you are wasting money- R-12 is very expensive now- last i checked its $60 per pound. the best way to remove R-12 is to take it to a shop that has the proper equipment and have them evacuate the system, most shops will do it for free if you let them keep the R-12.
when switiching over to 134, replace the reciever/dryer AND the orafice tube/ expansion valve. both parts are cheap and will definately make a difference in how good your a/c works on hot days in traffic.
when you are ready to recharge the system, have it vacuumed down to check for leaks. this also removes all the air and moisture from the system which will make it work better, and allows you to put the right amount of 134 into the system without over pressurerising it.
the suction line it the one you charge the system at- you will see 2 service ports, one is attached to a large diameter line and the other is on a small line- the large diameter line is the suction line. do not under any circumstances try to attach to the high pressure side of the system to fill- the can will explode in your face!
like naj said, make sure the front of the condenser is free of debris, and that any air deflectors are in place. if any of the fins are bent, take a pair of needle nose pliers and straighten them out or you can buy a fin straightener from most auto parts stores ( only a couple bucks- works like a comb) any bent fins restrict airflow throught the condenser affecting performance, and will also create hot spots in your radiator
oh one last thing- use a new belt or at least make sure the belt is tight. nothing annoys me more when im sittin in traffic and the car next to me has a loose belt and the light turns green. SQEEEEEAAALL!! , which causes me to throw my soda at your car.......

[MoparGLH]

Well,today I turned on the A/C and now the compressor clicks on and off.Should I put in the other can of refrigerant left over?The compressor clutch turns ok,but like I said it constantly clicks on and off.

[4Daytonas]

Yeah It's probably low.My 87 Voyager was only cooling a little and the compressor was cycling.Added a can and it was fine.first time I've had to add since retrofit 3 years ago.