zomeizter Posted July 27, 2015 Share Posted July 27, 2015 Hello all, I have a slight issue completing the A/C conversion on my 86 MJ. It is a factory equipped R12 system which I have completely flushed out of any residual oil from all components. I have installed a rebuilt compressor, new accumulator/drier, new expansion valve and replaced every o-ring throughout. The problem lies on one of the fittings, the high side to be exact. I had no problem on the low side since this has a shrader valve to keep the refrigerant in when I remove the charge hose from it, but the conversion fitting for the high side lacks this shrader valve, which causes the refrigerant to escape if I remove the high side charging hose. Does anyone know where to acquire a high side conversion fitting with a shrader valve? Is there a different way to go around this issue? BTW, when I charged the system and had it going, icy cold air was coming out of the vents. Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted July 27, 2015 Share Posted July 27, 2015 You don't charge A/c from the high side , that is only to meter the pressure . My advice is to put the high side port back to the way it was with the r12 , charge with the correct amount of 134a freon and call it a day . Link to comment Share on other sites More sharing options...
zomeizter Posted July 27, 2015 Author Share Posted July 27, 2015 Thanks Stroker, unfortunately the original port caps were gone and I had a hard time finding one to seal off the high side, but after an hour of searching I found a 90 degree high side swivel adapter with a shrader valve at O'reilys, (in case someone needs one it is P/N 59986) got her dun! Link to comment Share on other sites More sharing options...
docivy Posted July 27, 2015 Share Posted July 27, 2015 Is this a 2.5 or 2.8 Link to comment Share on other sites More sharing options...
zomeizter Posted July 28, 2015 Author Share Posted July 28, 2015 2.8L Link to comment Share on other sites More sharing options...
docivy Posted July 28, 2015 Share Posted July 28, 2015 I'm in the process of getting a 2.8 mj on the road. Good to see someone else running it Link to comment Share on other sites More sharing options...
zomeizter Posted July 29, 2015 Author Share Posted July 29, 2015 When I got this thing, it had spun a bearing and was noisy but soon after I bought a 2.8L HO out of a Camaro with a fresh rebuid for dirt cheap so I had to go with that setup. If I hadn't scored this motor I would have transplanted a 4.3L or a SBC drivetrain. It runs beautifully now and I will keep it this way till the ghost is released. Now back to the A/C on this truck, I thought all was well after the retrofit but something has failed and I think it's the expansion valve, here's what's happening. Once I had all the right fittings, I performed an evacuation and proceeded to add the refrigerant but it would not take it for some reason. I had the compressor going but both high and low pressure gages read at a steady 100 psi and the air out the vents was a little cool, nothing like the first time I charged it. When I replaced the o-rings throughout the system I came accross some kind of check valves in the solid line going to the top of the receiver/drier. I proceeded to change the o-rings on these valve looking things and reinstalled them. Well, after the issue with the refrigerant not wanting to get sucked in the system, I went ahead and opened up the solid line fittings where the check valves are and noticed there was a lot of pressure being released from both sides around such valves. After I got the lines disconnected, I took the valves out and connected the line back up without the check valve thingies. Again I performed an evac and tried to charge the system thinking those valves were the culprit but the refrigerant will not go in, as soon as I press charge on the charging station the gages jump to 100 psi and that's all I get, only about 0.15 lb of refrigerant goes in. I had to come home from work and stop the diagnosis, I will remove the new suspect expansion valve and install the old one to see if that's causing this problem, will report results tomorrow night, peace... Link to comment Share on other sites More sharing options...
docivy Posted July 29, 2015 Share Posted July 29, 2015 Dang that's no good. This winter I'm doing a motor swap on mi e then putting a 100% new ac system in. Not looking forward to these problems Link to comment Share on other sites More sharing options...
64 Cheyenne Posted July 29, 2015 Share Posted July 29, 2015 Did a 134 conversion on a New Yorker, the low side conversion had a schrader valve in it, when I went to fill the system it would not take refrigerant. I removed the stock schrader valve from under the converter, 134 went right in. Seems the plunger thing on the converter wasn't pushing on the stock valve or wouldn't let it through. After removal, all was good. Link to comment Share on other sites More sharing options...
zomeizter Posted July 29, 2015 Author Share Posted July 29, 2015 I think I figured it out, I have the service valves blocked off, will verify this afternoon, standby gents... Link to comment Share on other sites More sharing options...
zomeizter Posted July 30, 2015 Author Share Posted July 30, 2015 Got it! The problem was in the service valves, I backed them out all the way which caused the service ports to be blocked off, hence the inability for the refrigerant to enter the system. Nice and cold is the air out the vents now, which makes this Beaner very happy and my work commute much enjoyable in this hellish heat. If anyone cares, total oil charge was 6oz and refrigerant charge was 1.8 lbs. Pressure readings while in operation are 175 psi on the high side and 30 on the low side, peace. Link to comment Share on other sites More sharing options...
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