Brake pedal to the floor

[Bossman963]

Hi Guys & gals Ok have a problem and I have a 68 Charger that has a 440 in it and this car has been sitting since 1980 & all original- so my problem is this and its in 2 parts.

#1.- I replaced the master cylinder- bench bleed it and installed it on the original booster. I also replaced the rear wheel cylinders that were pretty nasty .
The brake pedal stays about 2" off the floor board, dash light say system failure, I didnt replace the front wheel cylinder because I going to convert it over to disk brakes.
What would keep the pedal @ the floor & I dont or cant fluid to the new rear wheel cylinders- could it be the proportioning valve went bad - can they be rebuilt.

#2- should I install a new dual type booster ? instead of the original single booster and will it hurt  or is there a difference in disk or drum master cylinder ? Will it hurt if I use a disk/drum porportioning valve ?

thx in advance Mike

[y3chargerrt]

Have you checked the front wheel cylinders? Sound like they are shot as well. What about the rubber brake hoses? Sounds like its time for that disk brake kit.