I can drive from S.C. to CALI with my gas turned "OFF".
I have rebuilt two seperate units and got the same thing. The second one I drilled out the rivets, replaced the internal "O" rings and stretched the spring a little to put a more pressure on the ball as it sits in the seats.
I rebuilt it as a manual and plugged the vacuum ports. I have the in-line solenoid for innshurance against liquid lockup, which of course we know can be rather devastating.
It's a pizz poor design but looks nice with the plastic chrome dial an all.........
Who knows.......maybe I don't know what I'm doing with these petcocks.....I can never rule that out!
