i am planning on doing a changeover from the old r 12 system to 134a. i plan on replacing the condensor,oriface tube, accumulator , o rings and anything else that it needs. the system works now and was done diy with one of those $32 changeover kits from auto zone. it hold pressure and blow semi cold but i want to tear it down, minus the compressor and replace the parts mentioned to prevent black death. i am taking it to an ac shop tho have it pumped out and properly discharged before doing so. once i get the parts replaced i would like to charge it myself as i have the gauges. my question is how much ester oil should i plan on addinng to the system if i completley drain the system? ive been looking for the service specs and cant find them. im not a trained professional but if all else i can take it to one to charge it but id like to know for myself how to do it. does anybody have any links or info on this particular system ? any tips? like i said it works now but it could be a little colder which is why id like to tune it up. also it has factory installed air and i am a bit confused on which or if my system has both an oriface tube and expansion valve or both. from my understanding it will have one or the other correct?

 

I changed mine (1989) a few weeks ago and it blows cold air, around 38-40 sitting still on a 82 degree day. Your system suppose to hold 3lb. 4oz. of R12 I put 2 cans of 12 oz. 134A with lubricant and sealer and 2 12 oz. cans of just 134A and it work fine.

 

i checked with a buddy who has all data and he said the system holds 12 oz of oil total. im going to have it drained out and change out the oriface tube, accumulator and the condensor and o rings on the lines and fill it. hopefully it will be a bit colder. im told by the same buddy to use the same color oriface tube that i pull out. i live in florida and it gets hot during the summer so i was considering one of those severe duty above 105 degree type oriface tubes that are self adjusting. i have heard poeple say good things about them but im not sure if i should just leave it like it was setup stock. any a/c experts?

 

I converted my 83 to 134A and change only the accumulator. System worked great. I charged it till it worked right. I have used machines but at home I do it the old fashion way. I go of pressures for that given day and get them to be cool and sweating on the low side pipes. Can't go off temperature at the vent. That can change from day to day.

You don't have a expansion valve on that truck. You have the orifice tube and accumulator system.

 

how the hell do i get to the oriface tube? its in the evaporaor line where the liquid line goes in but the damned thingwill not come out. is there a special tool or do i just cut it out with a tubing cutter and get a repair kit? does it need to be flared or is it one that has the ferrule hose fitting that is self crimping? i could not bust the fittings loose on the upper hose from the accumulator or the one from the evap to the accumulator either , they seem to have fused themselves together, i ended up stripping the fittings with 1 1/16 line wrench! im just going to have to get a new hose and possibly an evap repair kit. anybody know how well those things work?

 

They can be very tough to get out. I have seen them fly across when shop air is applied. Hard to do on this truck though.

I have always been able to wiggle them out but they can have you pretty POed before it's over.

 

You need the disconnect tool. The joint is held together with a spring. The tool spreads the spring to allow the two pieces to come apart. Some fuel lines use this same kind of connectors. With the tool it can be simple and some times it can be a real be-at-ch.

 

Forgot to mention that it is very common that when you take AC lines apart that have been together for awhile they tend to pull threads and then you have to replace them.

I have heated them with a propane torch and gotten them to come apart ok but make sure your system is empty before you do that.

 

yea i am going to try the disconnect tool, i saw that last night after some searching online. as for the lines i tried a torch i soaked them in pb blaster 2 days prior and then torched them before i tried last night. i got so pissed i cut the accumulator off and tried an inpact socket on the end i cut off and held the other end with a wrench to no avail. its the same on both sides of the accumulator. the one im concerned with is the one on top to the evap, if i have to cut it, can i get a repair kit that uses a slip over ferrule type connector to replace the cut off flare fitting? advance auto parts carrys an evap repair kit for like 23 bucks an di may just order it to see if it will fit. i figure its better than 100 for a new evap and the labor it will take to get it out of the box is another story. a new line is only 38 bucks so im going to go on ahead and order it because i know im going need it because the threads are fused. hopefully the evap repair kit will be what im looking for on the top sideand i can just use a tubing cutter and replace it? im not sure which one i need though, i think the top one is the one.

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update, after soaking the fittings overnight i was able to crank up the pressure on my air compressor to about 150 psi to where if it didnt break the fittings loose they were comming off evaporator and hose intact. i was able to break them both loose, evac and flush the system, change all the o rings,put the new accumulator in,change out the oriface tube that had a little bit of gunk in it but nothing black, blew out the evaporator and flushed it with some clean oil and flushed it out again to see the oil looked clean after cycliny through,hooked it all up, pulled vacuum and check to see if it held, which it did after an hour or sitting so i charged it with a can of 2oz 134a and 8 1/2 ester oil and 3 12 oz cans of advance auto parts brand r134a to 45 psi on the low side and about 255 on the high side with air that will freeze you out on the high fan setting on a 95 degree day in central florida at idle. im going to check it tommorrow evening to see if it has lost pressure but im pretty sure its good to go! thanks for the tips guys i now feel confident working on a/c systems, next up is my 94 toyota, gonna give it a new expansion valve and accumulator and tune it all up.

 

the factory spec on the 89 , all oil removed , the system requires 10 ounces

 

i dumped 2 oz into the accumulator before i charged it so i actually ran 10.5 oz give or take. sumbitch blows cold and hasnt leaked since i did it, compressor seems to be warm not too hot to touch after a 30 min drive with max a/c on so im calling it good.