I am finally finishing my 1927 T. Evrything works great except the rear brakes. I have a dual master cylinder mounted below the floor - disc brakes on the front ad S-10 drum brakes on the rear. I have new cylinders, drums and shoes on the rear. I have the 10psi valve on the rear and just after it I have the propotioning valve. Right now the proportioning valve is opened up all the way (counter clockwise). I have bleed the brakes numerous times - but when I bpress on the pedal the rear tires still turn. I am stumped.