DatsunZman04 Posted May 7, 2013 Share Posted May 7, 2013 I have purcased the toyota 4 piston calipers from a 84, I assume its th S12+8 version and got a decent set of pads. This is going on a 240z street and possibly once a year time trialing in the KC football stadium parking lot. I have done my research about this mod and dont want to be beating a dead horse but I do know you need the larger brake master cylander. Heres my question?? I have a brand new 300zx brake master cylander and booster asseymbly and was wondering if its large enough to handle the load of the new brakes. Next question? Will it have the same size fittings on the bottom/sides for the brakes since It has one resovoir instead of two?? Heres a pick of what I got, any help would be appreciated. Should I go with this setup or just buy the bigger 280z brake master cylander? Heres a noob question, why is their a differenace in brake rotors for the 72, 240z and the 74, 260z?? Black dragon and msa sells cross drilled and sloted rotors for the 260 and up. I thought the 240 and 260 front hubs and rotors were the same but I guess I am wrong?? Quote Link to comment Share on other sites More sharing options...
z31restore Posted May 11, 2013 Share Posted May 11, 2013 i know those master cylinders can run a set of 2 piston cals but i dont think 4. id be going with the bigger 280z master cylinder. im doing brake work myself so ive been doing a little research too. also with the fittings i would be willing to bet theyre not the same but its not hard to find adapters for them. also what version of the 300zx cylinder do you have, a z31 or z32? come to think of it a cylinder of the 350z would for sure run those cals. good luck hope i was of a little help. Quote Link to comment Share on other sites More sharing options...
Nigel Posted May 11, 2013 Share Posted May 11, 2013 The number of pistons has nothing to do with the fluid volume of the caliper and everything to do with the combined surface area of the pistons. A caliper with two large pistons could have more piston surface area than a caliper with 6 small pistons. The master Cylinder bore diameter in relation to the caliper piston surface area determines the pedal travel and effort. Datsunzman04, it sounds like you're using the non-vented rotor version of the Toyota caliper. These calipers actually don't have that much bigger combined piston surface area than stock 240Z calipers. So, you don't necessarily need to upgrade the master. You'll have slightly longer pedal travel, but less effort will be required. Master Cylinder specifications are readily available on line. If you install calipers with a significantly larger fluid volume than stock, then you need to fine a master with an appropriate bore diameter. Stock is 7/8". The 280ZX master is 15/16". Quote Link to comment Share on other sites More sharing options...
DatsunZman04 Posted May 13, 2013 Author Share Posted May 13, 2013 Thanks for the info, I guess I need to measure the z31 and see what the size is and decide if its worth swapping everything over. I just didnt want to buy a 15/16 when I might have a possible solution on hand. Quote Link to comment Share on other sites More sharing options...
my1path Posted June 6, 2015 Share Posted June 6, 2015 (edited) Info for newcomers to this old thread. The Z31 MC was 15/16 and has all the same fitting sizes (M10x1.0) but different locations.There are several sizes out there for the newer Uni-reservoir MC. (Z31, z32, R32, pathfinder, late 80's & 90's cars) But their bore is not always labeled clearly so this is how you can decode them.BM33 = 13/16BM38 = 7/8BM44 = 15/16BM50 = 1"BM57 = 1 1/16 Edited June 6, 2015 by my1path Quote Link to comment Share on other sites More sharing options...
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