So I have put a hr disc front end into my eh wagon. I have put hr slave cylinders on the rear with hr shoes. I have also put a hr disc master cylinder on the firewall. Brakes are running through a vh40 booster. Booster, cylinders all brand new. I have bleed the system starting with master cylinder, then booster, then rears then fronts. Brakes build up pressure/pedal just fine and hold pressure fine. But as soon as you release the pedal, wait two seconds, the pedal will go straight to the floor again. I cannot find any leaks in the lines. Why does the brake pedal keep going to floor? I have bleed the whole system five to six times!

Yeah, brake shoes are adjusted correctly. Yeah they are hr disc cylinders with hr shoes...Since yesterday I pulled off the front calipers, they looked seized, so I will rebuild the calipers and try again. Thanks for replying