[Jim Smith]

Hey guys just realized I never posted a follow-up with the solution to this problem. Upon inspection with a mirror and flashlight we noticed the tiny ball that pops into the detent appeared to be missing. Removal of the valve confirmed this. We replaced the spring and ball and everything is fine. Amazing how one tiny ball bearing sized item can create such a major and potentially deadly issue. Not sure if the ball popped out on it's own or when the valve had been removed and serviced by a mechanic previously.