Bad Prop Valve???

[grayw0lf]

Do I possibly have a bad prop valve, or am I barking up the wrong tree?

I just installed my disc brake conversion kit. All fittings seem good & tight. I bled the MC & at all 4 wheels. My brakes seem perfect for the first dozen or so stops... but then the light comes on & it feels funny.

Here's the weird thing that makes me question the prop valve. The fluid level of fluid in the back chamber of the M.C. goes down, the fluid level up front goes up!?.

The MC is new & for a 71 C-10. The prop valve I think is from a 71-72 3/4 or 1 ton. I made new lines from the MC to the prop valve. Front resorvoir to the front & back to back, normal for a C-10.

Does this sound like a bad prop valve? Other suggestions?