Replace entire system and brake Paddle is still almost on the floorboard. Free-play for Brake Paddle is right and the Booster Rod adjustment is right. Bench Bled Master Cylinder. Pressure Bled system in correct order. New lines, New Vacuum Lines, Check Valve.
New Proportioning Valve, as I've said everything is New!!!!!. I've ran every test like the Repair Manuals says to try and find out what is wrong no go, No air in system I've ran about 2 1/2 gal. of brake fluid Dot3 through it. It is a 1986 Toyota 4x4 pickup.