Proportioning Valve Keeps Tripping?

[KyleSeal]

Originally Posted by MikeB

My almost-new switch all of a sudden got very sensitive, even when not applying the brakes. I pulled it out and checked it on the bench with an ohmmeter. Turns out that just a very small bit of upward movement causes the switch to close. I mean we're talking .050" if that much.

Ended up using the later model switch that came with my aftermarket combo valve. Unfortunately, the wire connector is different, but that's no big deal -- just another PITA to deal with.

This is probably not your problem, since your switch closes only when you step on the brakes. But I just wanted to get this info out there -- the light flickering or being on all the time could indicate a bad ChiCom switch.

On another note, that's a dual 8" booster, right?

Yep - 8" booster. I did flush mount to the firewall, which I was thinking may be a problem, but judging by what others have told me I am thinking I have some air really stuck. Im going to try a heavy hit to the pedal with the bleeders open and see what it gets me. Hopefully not a mess to clean up!

Originally Posted by Rust_never_sleeps

Maybe try adjusting the backs to be stupidly tight and see if that makes a difference.
IF you still have the differential pressure valve moving, then there's air or fluid loss somewhere causing a....pressure difference

I actually did adjust them to the point where the wheel wont turn. Still the same. I am thinking I have a huge bubble somewhere and its possibly in the rear circuit at the prop or in the prop valve.