I'm installing a UP6 brake valve in my 4th jet, so I've done this before. Both air lines are hooked up properly, one in the other out, both on the correct sides - however once the pressure gets to 40psi the small pin hole in side of the valve near the "air out" side startes to let air out. Anyone know why?

Maybe that's exactly the problem, on mine, the pinhole is on the "air in" side, swap your lines and try again...

Ruizmilton - thanks, I guess the valve was upside down...its all set.