hello mate
have you replaced the rubber hoses. because they can detereate inside and allow fluid to the brakes but not flow back and cause the brakes to bind!
jack the car up, remove the rear wheels and get someone to applie the brakes untill they are binding when the pedal is not pressed. then slacken the bleed nipple if fluid squirts out and the brake does not bind that is the problem. also you dont say weather you have replaced the hand brake cable. make sure that move freely
hth nick.