[encantotom]

these valves fail in just a couple of ways.  

1.  the plunger seal gets scored such that it no longer completely covers the orfice in the body of the valve.  only solution is to replace the plunger.  how does that happen you ask?   our air systems have moisture in them and cause rust in the tanks.  that rust flakes off and gets between the seal and the orfice and causes it to score allowing air to get by when it should be sealed.  

2.  the 12v coil.  that is very very rare.  

3.  an o ring failure.  there are 2 orings on the outside on the bottom as you see where they go in the picture.  and one internally.  rare failure too

4.  in the picture below here is a valve body that has a metal failure in place where the o ring goes.  you can see it is mis shappened.  i am making the assumption that this happens if the valve is overtightened on the six pack manifold.  so dont over tighten them.  make sure you have some o ring grease on the rings and tighten snugly.

tom