71ChallengerSE
A, B, & E Owner
Problems with Inline Tube reproduction disc proportioning valves. I have always used originals on my projects, but five years ago I used a reproduction on a friend's '70 Duster with a factory-style '73 Disc/Drum combo. The brakes have always been bad: spongy and soft. He never complained, but I hated it. He also trashed his new rotors and pads within a year. This was a clue! Anyway, while using a vacuum bleeder, the rears bled fine, no problem. The fronts would not pull fluid. I even pulled the bleeders and let it gravity bleed overnight on the lift, only to find not a drop had leaked out. I traced it back to the prop valve. Fluid would flow to it but not out. Did I mention every bit of this brake system was brand new, including all the lines from Inline Tube? I pulled the valve and tried to blow through the master port, and no air would come out of the ports for the left or right calipers. I grabbed an original Weatherhead valve and did the same. It passed air, no problem. After disassembling both valves, I found some interesting details. Inline Tube copied the Weatherhead valve almost exactly, but they left out several details. First, the repro is missing the lower internal piston, which allows the idiot light to function if the piston is moved too far in. I don't see how the idiot light could possibly work at all on the repro. Second, the real problem is the missing three bumps on the upper washer in the front disc piston. Those bumps allow a clearance for fluid to bypass and bleed correctly. Without those bumps, the fluid has a hard time getting to the calipers, and if it does, then it can't move back, causing the calipers to drag. I bought a second repro from Inline Tube, and it had the same defect. A friend's Challenger had a problem with one of the ports not drilled all the way through. That was fun to diagnose. Anyway, I took a flat-blade screwdriver and a hammer and pounded three notches into that brass washer and reassembled everything. It bleeds properly now. These parts are not manufactured correctly and could be dangerous.
