Proportioning valve problem

[box]

I've only seen it twice before - once was on an early 90's Mitsi, the other was on a mid 90's Hyundai. Both were non ABS vehicles, both had likely never had their fluid changed before and were only picked up due to having a rear brake imbalance on the brake rollers during vehicle inspection.

If you get a chance, could you pull the old one apart and let us know what's gone wrong?

[stealthee]

I've thought about opening it up to inspect it just to see what the hell happened. I'll have to see what I can do. Since it is a cast piece I think I might just try to cross section the whole thing.