Am working on the AC system on a '72 Fury that was in storage many years. Installed new clutch, rebuilt compressor, new expansion valve (twice), receiver /dryer, and EPR valve/ suction filter. Low side pressure is too high -- around 60, high side is around 110. Frosts at the EPR valve location on the compressor. Blew out all lines and evaporator / condensor, flushed system, tried both r-12 and r 134a and still have same situation. Anyone out there that could give my mechanic some advice? Thanks John
It sounds to me you have a restriction with that expansion valve.
Also make sure your running the proper mineral oil if you are running R-12.
R-134 takes different oil to run the sytem.
Also, have you done a complete evacuation of the system with a pump?
The system must be drawn down to -30in hg. for 30-45 minutes after closing up the system.
Thanks for the reply. We did flush the system then pull a vacuum. Using an ester based oil which is compatible with either freon but are using 134A. Will try replacing the expansion valve again. Thanks, John
That EPR could very well be the problem. Since you have had everything else taken care of, I beleive it to be that.
I"m sorry for getting back so late.