Someone PLEASE come up with an answer for this. My 37 Buick worked fine for 30 years with a drum-drum dual master cylinder and power booster. Got caught in a dicey situation in Kansas City during a monsoon where the drums were under water so decided to put discs on the front. Put the disc-drum dual mc on and even the hubcaps are hot to the touch after ten miles. Decided the supposed to be 10# drum and 2# disc residual pressure seats in the mc were wrong so to test I put the old mc back on after drilling through the flare seats to eliminate ANY residual pressure. Same thing so replaced new hoses that came with the disc kit with two more new hoses. Same thing. Took some 3/16 steel line with a double loop and replaced rubber line for a (very) temporary test. Same thing. The link from pedal to booster is floppy loose when spring retracts pedal and have shortened the rod from booster to mc till the pedal has gone from near full height to 1.5 iches off the floor. When the car stops as soon as you leave up on the gas I jump out with a 10mm wrench and crack the bleeders which makes it completely free. Summary: NO rubber lines, NO residual pressure valves, rods NOT touching the booster or mc, what's happening? Oh yeah, used spare mc cap with two large vent holes in it for testing. Drove into shop while nearly sliding front wheels and cracked left bleeder--wheel spun free but right side was still nearly locked.
