So i finally finished my 300zx bbk setup, did new pads and rotors in the rear with SS brake lines all around. The brakes were bled and yet the pedal feels like it has a lot of play, like its loose almost. IS this normal with the conversion? because i swear i read something about the pedal feeling different. Could my Brake master cylinder or booster be going? idk what do you guys think?

 

what happened is your brake bias is way off and sence you went from one piston brakes to 4 piston brakes, your master cylinder isnt able to keep the same volume/pressure ratio, which in turn gives it a softer pedal feel, the best way to combat that is to do the 300zx rear brake option as well to keep your bias in check and to get a larger master cylinder to boost the pressures

 

I kinda figured that.... damn the rear swap is way out my budget right now and i have lots more to do. Whats up with the master cylinder swap. is it hard"?

 

depends how mechanicly inclined you are. its not all that hard for me because its right there so to say, unscrew the lines disconnect the pedal and once you unscrew the master cylinder it comes off....now i am skiping a few steps...but to be honest if its super spongy than you still have air in the lines/calipers....i ended up having to bleed the hell out of my system when i did it because when i unscrewd the lines to put on the conversion, air went all the way up to the master cylinder and even though it might not look the part there was still air in there that i had to buy a vacuum bleeder to get it out cause i was to impatient

edit: i dont know if the 5th gen setup for the master cylinder is different i have a 95, but he same concept is still there

 

It's mainly because the 300zx MC puts out better pressure.

The argument of going from single piston to 4-piston is only because of the MC difference for the 300ZX setup.
You could buy a Stillen or Wilwood 4-piston setup made for Maximas and not have an issue with MC pressure.