Got's an 80 CJ-5 came with manual brakes, front disc and rear drum. Switched to rear SSBC disc's and now i cant get any pedal pressure???? And it's also a brand new master cylinder.....none of that rebuilt crap Auto Doom sells. Tried to tear apart Proportioning valve.....yea i might as well be looking inside a computer......i have no idea what to remove as some people say??? So anyways I got to reading......yes i know guys... it's a scary thought and all, but me??? read??? haha But i kinda came upon the conclusion that i mite need a master cylinder made for FRT and Rear discs. A 68' vette MC came up alot but i figured i might need to get ahold of one of them and a proportioning valve from a CJ with FRT and Rear drums for a 50/50 split i hear so much of.......SO guys and gals.......wudda ya all think bout it?