First off I have a 73 FJ40. It has disc brakes on the front and drums on the back. Just had new brakes installed-new calipers, pads and rotors for the front and drums and cylinders for the rear. Still have original brake lines and brake booster. After installing everything and getting fluid to it. The brakes completely locked up. So me and my mechanic bleed everything down, first at master cylinder then at each wheel (DR,PR,PF,DF) and still have same problem. Installed new master cylinder and bleed everything down again starting w/the master. After testing brakes, had good front brakes but no rear brakes "at all". So bleed the rear brakes again, now have good drum brakes but the front disc brakes are locking up again. What the crap??? No leaks, and getting good clear brake fluid when we bleed each wheel down. Suggestions???