I am trying to remove the AST valve so I can do a pressure test on it. The valve itself says "NEVER REMOVE" however the mazda shop manual says to take of the vave and attach it to the pressure tester and check it can hold 20.6 psi for 10 seconds. I have a few quetions
1. Will removing this valve (the one on the black plastic AST) to test it hurt anything?
2. Are their any tricks to removing it?

 

Is that the stock plastic AST? I think i read somewhere that replacing the plastic AST with a metal one (or removing it altogether) is a recommended "reliability mod". maybe look into it and it will solve your problem AND make your car a little more bullet proof ;-)