Do I need a new disc-brake proportioning/centering valve?

[cris well]

I've been having problems with my C-10 68 converted to 71 disc setup.

The truck will stop but the brake pedal is really hard to push and It won't lock the brakes down if needed--just slows the truck down.

I've searched and read through many threads and think I may have found the problem.

My proportioning valve button is pushed in and stuck. First I stomped on the pedal with the front lines un-hooked and all the fluid out of the master-cyl. with the key switch on (didn't work).

Then I took off the prop. valve and tapped on it really hard from all angles (didn't work).

Then I blew through the front brake line with an airline while holding my finger over the front outlet on the bottom of it and the button will pop out while the air is on it but pops right back in when I take the air off.

Should I put it back on and try it or should I get a new one?



I've already put a new master-cyl.and booster on it, and was in the process of putting new brake hoses on it when I started looking in to the prop. valve. I'm gonna put the new hoses on and try it again I think.