Has any one taken one apart? If so does the little valve located deep in the valve body come out? I have a situation where ive the rf brake pads worn way down before the left side. This is after caliper, pad and rotor replacement. The rf wheel has more brake dust and i can feel a little pull to the right when I brake. I got a replacement froma junk yard and took it apart all came apart except the valve deep in the body. Pulling with a long nosed pliers didnt work.

 

The proportioning valve only controls front/rear brake pressure, more to front discs than rear drums. 70/30 usually.

The combination valve prevents the lose of front or rear brakes depending on where fluid pressure is lost. Vehicle will always have brakes at one end or the other.

Side to side brake lockup is caused by plugged lines. Front is usually the flex line is breaking down inside and gummy rubber is plugging the line. Replace both fronts, mine only lasted 12 years. Collapsed rubber line interior prevents brake fluid bleed back when brakes released, brake drags.

Brake fluid contaminated by water turns into strong acid.

Blow all the lines out with compressed air, brake cleaner then compressed air again. New fluid

 

Replaced both brake hoses as suggested. Pedal feels a little different. Looks lik the ac drips on the hose mounting bracket creating rust and crud. Will keep you posted on he brake pad wear

 

It could be the caliper sticking. Have you overhauled the calipers?

 

Even without the AC dripping on the bracket, it naturally traps moisture by the sleeve that's supposed to protect it. On mine, the sleeve also cut into the brake hose:

https://plus.google.com/photos/11555...67774490549511

I modified the sleeve with a V-cut at the inside bend on the new hose.

 

This is after caliper, pad and rotor replacement.