Okay so switched over to a disk brake from a factory drum in the front if my 73 duster. Took all the parts I needed off of another car but the combination valve was missing so I bought the one from inline tube for front disk and rear drum brakes. Well I bled the system and what not but my light will not go off! And the brakes are funny because if you hit them hard and fast it comes to a stop mid way and only locks the front brakes then if you ease off the pressure a little bit the pedal will then go down farther and lock the rear and fronts together like its supposed to. It is bugging the heck out of me and I donno what to do. Open to all options thanks!! Btw everything is brand new master cylinder, calipers, lines, and so on....