Idk what's wrong with my ac the clutch wont engage their pressure in the lines I had to manually get it to turn on meaning I used some gasket maker the felt and cut out rings the size of the compressor clutch and stick in their to get to spin over to charge but after I charged it the clutch...
www.stangnet.com
Bottom line. Not all models have traditional replaceable valve cores. For these cases there are aftermarket "service" replacements that will hold the old valve open and add a traditional Schrader valve.
Other models have non replaceable valve cores but the port can be unscrewed from the line. Look close to find out which kind your have and which solution makes the most sense for you.