Automotive Air Conditioning Information Forum

GM high side port has a high side has like a rubber ball inside. Think it comes that is OEM. Looks like the replacement port also has that rubber ball. (It is leaking slightly. Doreman makes a brass screw that is screw that supposedly helps to prevent any loss of Freon. Have not tried it yet).
I tried 2 sets of 134a connectors from different brands. Neither could push the ball in far enough to depress the Schrader valve. Trying to avoid changing the port.
The replacement ports might come with ball also.
Any way I can get a high side reading?
Do they make a special coupler for that valve?
Thank you

To avoid problems with the GM high-side service port now and in the future, I would get rid of the troublesome "rubber ball" valve and replace it with a traditional Schrader valve fitting, available in the market, that will accept a standard gauge-set coupler. Yes, it's more work and expense in that you'll have to recover the charge, replace the fitting, evacuate, and recharge the system. I think it's worth it, though.

Thank you

Why not just put a good cap on it with a good rubber seal? The "ball" is designed to only seal long enough to attach a gage set without blowing out the charge. I test my leak detector on the uncapped port to see if it is working, then I cap it off and there is no leak found with the detector.

As many times as this subject has come up- everyone needs to know that the plastic "cap" with the rubber element is the primary seal by design. The cap is not like a tire valve cap that is only designed to keep dirt out, it has a rubber seal to hold pressure. Many times,I have felt the cap "pop" off the port when unscrewed due to its "doing its job."

Those "ball" valves are replaceable- and anytime I've had issues with a coupler fitting right- it has always been in the coupler- not the port. Always be sure the depressor is turned back to the retracted position before trying to attach the quick connect. Once connected and seated, then turn the depressor down to open the ball valve.

Thank you