Brakes Front brakes heating up, pressurizing fluid, pedal stays up

Front brakes feed independently off the prop valve. The rear is a single line.

I wonder if it is the prop valve. Hmm. The port feeding that caliper could be partially blocked and not allowing oressure to release.

I forget. Does caliper free up if you crack a bleeder?

Was it ever pulled apart for any reason?

Ummmmmmmmmm....

I've now forgotten: Is this the same MC you started with?

This is strange. Cracking that bleeder should allow the piston to retract. Might take a few spins of the wheel to do it

I'm starting to think there's a blockage in your proportioning valve.

Which caliper is it again that is freezing up? The two front lines are split. One should go to the rear, and one comes off the bottom, rear port of the PV. I'm thinking one of these ports might be clogged. When you step on the brake pedal, you have more than enough power to force fluid past a blockage, but the natural wobble of the rotor might not be enough for it to flow back.

The problem is the fitting layout of the PV is different on the 87+ cars as they are a 3-port MC with one line direct, and a 2 port PV with 2 lines in and 2 out. The 80-86 PV is 2 in and 3 out. I also am not sure if the fitting sizes are the same. I believe the 87+ is a mis of 3/8-24 and 7/16-24 inverted flare.

The part number for the 80-86 PV is E0ZC-2B328-AA, You can either try to replace it, or remove it and rebuild it like the link I posted several posts up.

If you've replaced the MC, the calipers several times and tested the lines, it's the only think that it could be.

One more question. When you bleed the front brakes, do they both bleed at the same flow, or is the sticking wheel a little slower to bleed through?