my 91 Z is doing the same thing...i had my engine bay painted so i removed everything...when i put the master cylinder and booster back in i bled it....got a damn good pedal and then started losing fluid and it was running out of the drivers side...come to find out there is this little check ball looking deal on the side of the master cylinder that my fluid is running out of...but i have no idea wat this little check ball deal is for?..i don't know if it is a self bleeder of wat?