Losing my brakes this weekend was not a fun occurrence, and something I would like to avoid happening again. At this point I have some ideas on what may be part of the problem, but I would like some other input.
First let me describe my current setup. On the front I have new D60 calipers and pads, with the stock rotors (like new). On the rear I have new K20 calipers, pads and rotors. My master cylinder is from a late 70s 3/4 ton chevy (new), connected to the stock toy brake booster by way of a home made adapter. I'm using 36" stainless steel soft lines from the frame to the calipers in the front. For the rear I have a SS soft line from the frame a T on the axle, then a 36" SS soft line to each caliper. Most of the SS lines are from speedway motors. I also have line locks plumbed in for the front and rear, as well as a proportioning valve and residual valve for the rear.
From talking with others with a similar setup, I should be able to lock up the tires, but my brakes have never worked well, going from mushy to outright failing. I have bench bled the MC, but plan on doing it again. I've bled the brakes many times, but that does not seem to help the problem. One odd thing that has happened several times while bleeding the brakes is a stream of fluid will flow back into the MC when no one is touching the brakes. Its hard to describe, but imagine holding a running water hose under the surface of a pool of water, facing up so that the water coming out of the hose breaks the surface of the pond. I have no clue what it means, and neither has anyone else who has seen it.