AC compressor - low side hi - hi side low

I reconnected my 1964 Fords ac system. I replaced the condenser and receiver dryer with generic ones and hooked it all back up. Still has the York AC compressor. It held vacuum for 2 days. When I went to put freon in it and could only get a little more then one can in. The high side plumbing gets hot and there is some cooling in the car but not a lot. You can see freon running past the sight glass. The pressure gauges only show a 10 psi difference between the high side pressure and low side pressure. The pressures run around 80 on the low side and 90 on the high side, varying up and down depending on engine speed but always about 10 psi apart. To try and test the compressor I used the valves on the compressor to close the hose end and just leave the port connected for pressure readings. When I close the high side it will run the pressure up past 300 psi. But when I close the low side it only pulls it down to 55 psi.

Any thoughts on what the problem is? I'm thinking its either bad expansion valve or bad compressor. Most new systems have no trouble pulling the low side down to 25 psi or less but I don't know what these yorks are supposed to be able to do.

Reply to
Ashton Crusher
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Sounds like a bad expansion device to me. Try tapping on the expansion device while the system is operating and see if you get anywhere.

Also be aware that the shaft seal on the compressor is likely to fail in short order if the system has been sitting for a long time.

Steve B.

Reply to
Steve B.

Solution turned out to be for me to get my head out of my butt. I had both valves on the AC Manifold gauge set open at the same time. It had the effect of looping the freon thru the gauge manifold instead of the AC system. So no pressure build up and nothing to suction against. Closing the hi side manifold valve fixed the pressure readings and allowed me to put the rest of the freon in. Now it seems to be working properly.

Reply to
Ashton Crusher

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