240Z Turbo Posted April 24, 2003 Share Posted April 24, 2003 I had swapped the brake master cylinder in my car to a 17/16" brake master from a 90-91 300zx(N/A or TT). I was using the stock proportioning valve and noticed on the dyno that when I used the brake the back would not stop. I learned these master cylinders are internally proportioned. So I just bypassed the stock proportioning valve and splitter and made my own break lines(3/16") with metric fittings on one end and standard on the ends where I used the "T." I also added in a Wilwood mechanical proportioning valve for the rear. I will let you know the results if I ever get the car running again! Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted January 8, 2004 Share Posted January 8, 2004 hey i was just looking for info on this swap but instead i was looking at the 1990 300ZX's 1 1/16th MC. They had 2 different ones, Neapco (17/18ths or somthing) and tokico (1 1/16th's). There may be a probem with the center bore of the booster, but otherwise it should be a better setup the smaller as long as you are running rear disk. It also is set up more like the stock I beleve. I was reading an article for this swap in a 240sx. Only downside is it is bubble flair going into master cylinder. let me know whats going on, I couldnt find any updates on your set up yet. Ryan Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted January 8, 2004 Share Posted January 8, 2004 crap i misread your post. You said 17/16ths but i thought you said 17/18ths. My bad . So you were trying to run the one iwas thinking about. They are cheap too. They only run me about $45 for a lifetime rebuilt one. Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted January 8, 2004 Share Posted January 8, 2004 What is the rule of thumb for sizing master cylinder bore to caliper piston diameter. I know that increasing the master relative to the caliper will give a firmer pedal, and vice versa, but is there some rule of thumb, or is it all trial and error? Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted January 8, 2004 Share Posted January 8, 2004 There is a formula for determining which mastercylinder to use. But i think road racing with the JSK brakes in the front and rear disk may be more than the 280ZX one can handle. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted January 8, 2004 Share Posted January 8, 2004 I am running the 15/16" bore early 280ZX (I ordered for a 1980) master with 280 zx rear calipers and 4 piston Superlites on the front (don't know the bore sizes for the calipers ), and in initial testing, I have more than adequate braking and pedal action.... Tim Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted January 8, 2004 Share Posted January 8, 2004 Juan has a big rear disk kit he was working on and i am planning on running that. It is slightly larger than the 280ZX. i am just figuring that since the brakes will be more similar to the 300zx than the 280zx, i figured the larger MC would be better off. Quote Link to comment Share on other sites More sharing options...
auxilary Posted January 8, 2004 Share Posted January 8, 2004 has been for over a year now. He was using c4 brakes (front and rear) with it on his Z Quote Link to comment Share on other sites More sharing options...
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