more follow up: i took the advice of a friend that plays with these old systems a lot and re adjusted the valve to 26 psi. went fairly easy, the adjusting screw had enough resistance to turning that tightening the lock nut didn't change the adjustment. got it done in 3 attempts. hopefully, i can now...

"So it pops at 30 psi. No air comes out of the compressor suction end that you have open to atmosphere until 30 psi right?" there was no "pop" on the first two valves. and they wouldn't maintain the required back pressure when the shop air pressure was increased past 30 psi.

knock on wood, third time seems to be the charm. got the third poa from "The Parts Guy" here in florida and bench tested it this morning. as the pressure passed 30 psi there was the "pop" that some have mentioned and the valve settled down to about 20 psi and maintained that as t...

it doesn't really hold pressure. it doesn't pass any shop air until it hits about 30 psi. but as the shop air pressure rises the pressure on the low side of the valve rises with it.

well, the guy i bought the poa valve from was kind enough to send a second one. it tested the same as the first one, that is it wouldn't hold 30 psi on the low side gauge during the test. seems unlikely that two NOS/NIB valves would be defective. i'm out of ideas. another shot of the test setup: POA...

it's a delco part #15-5193

Tried to test the poa valve today. i set up the test rig as per the paper that has been referenced and posted here many times. the shop air is run through a drier and regulated to 75psi. as soon as i crack the high side valve on the manifold i can here air bleeding through the poa valve, there is no...

after the adjustment tools get here i'll have a go at it and post back. should be interesting.

john thanks for the info and doug thanks for the suggestion. a friend over at the corvette forum has graciously volunteered to send me his fitting kit just for doing the test and calibration on poa valves. i got lucky.

hi all, i would like to test and then recalibrate my POA valve for R134 using the procedure outlined in the link below. getting shop air to the red/high side hose and attaching the blue/low side hose to the valve is no problem. however, connecting the yellow hose to the inlet on the valve is. are th...