2003z Posted August 9, 2005 Share Posted August 9, 2005 73 240Z I've searched and read so much stuff that I'm even more confused now. I have S12W calipers front and 280zx calipers rear. Will the booster and 15/16" MC from 79 ZX bolt in, and is that my best solution. I don't want anything that I need to lengthen rods on, just a direct bolt in. Turning it upside down isn't a problem for me, neither is having to elongate mounting holes in the firewall. I've just read too many horror stories and want it to work right the first time. Also, should I gut my proportioning valves and install a Wilwood in the rear while I've got it all apart? thanks in advance. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted August 9, 2005 Share Posted August 9, 2005 I believe the booster will be too large a diameter (someone will correct me if I'm wrong) and the MC will require a small change in the rod length coming out of the booster. With the 240, I believe the booster will interfere with the clutch MC even if you go too large. I have a larger booster on mine, which is extremely close to the clutch MC (had to grind a little on the MC), and I believe it is a 280Z booster. There's not much "bolt on" stuff on this site, so get ready to cut, file, weld, and modify!!! Quote Link to comment Share on other sites More sharing options...
2003z Posted August 9, 2005 Author Share Posted August 9, 2005 so should I just get the 79 master cylinder and make it work with my booster? Quote Link to comment Share on other sites More sharing options...
jt1 Posted August 10, 2005 Share Posted August 10, 2005 You didn't say if your car is a manual or auto. The ZX booster won't work with a manual because it interferes with the clutch master cylinder, unless you want to move the clutch master over about 2", which is gonna get complicated. It's probably best to use the ZX master on your booster. Pushrod length seems to be hit or miss. Some people don't have a problem, others have to adjust it. posted by blueovalZ There's not much "bolt on" stuff on this site, so get ready to cut, file, weld, and modify!!! Very well said. John Quote Link to comment Share on other sites More sharing options...
2003z Posted August 10, 2005 Author Share Posted August 10, 2005 yea, its a manual. Looking at it, I could see there isn't much room at all. I ordered a new MC and will start with that. Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 10, 2005 Share Posted August 10, 2005 I was able to get the 15/16" master cylinder and the brake booster from a 83 280zx to fit in my early 260z. I had to turn the brake boost upside down to make it fit but all the holes and linkage line up perfectly still. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted August 10, 2005 Share Posted August 10, 2005 If you are not replacing the booster, then a 79 ZX MC is about as close to a bolt on upgrade as you can get. I bolted one up to my 1970 240 with zero problems. If you can turn a wrench, then adjusting the length of the push rod to get the brake pedal height you want is absolutely trivial. It is only in replacing the booster that you will exceed my experience level, but even that doesn't sound too horible. Quote Link to comment Share on other sites More sharing options...
loy Posted August 20, 2005 Share Posted August 20, 2005 I was able to get the 15/16" master cylinder and the brake booster from a 83 280zx to fit in my early 260z. I had to turn the brake boost upside down to make it fit but all the holes and linkage line up perfectly still. I suppose this is a picture with the booster from the 83 http://album.hybridz.org/data/500/DSC04469.jpg Did u have any problems putting it in besides turning it upside down? or pretty much just bolt on Quote Link to comment Share on other sites More sharing options...
rreford Posted September 11, 2005 Share Posted September 11, 2005 is there significant advantage to switching boosters? just picked up a ZX master cylinder yesterday, didn't know i should've/could've also gotten the booster. planning to fit to a '73 240ZT. Thanks! Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted September 11, 2005 Share Posted September 11, 2005 a larger diameter booster will create more of a pull for a shorter distance. Where as a smaller diameter booster as found in the 240z's will have a farther stroke but less pull. Whether or not this is enough to warrent a change i don't know. Will be intresting to find out, I am going to do the mc swap w/o changing booster so why doesn't someone try it with a changed booster. BTW pop n wood, does the rod need any length changes? You hooked your 15/16"s up to a 240z booster correct? Quote Link to comment Share on other sites More sharing options...
loy Posted September 12, 2005 Share Posted September 12, 2005 i've heard of fitting problems swaping the booster from the zx series if u have a manual transmission. The clutch thing is in the way Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted September 12, 2005 Share Posted September 12, 2005 BTW pop n wood, does the rod need any length changes? You hooked your 15/16"s up to a 240z booster correct? I used an MC from a 79 ZX in my 1970 240. When I first put it in, the brake pedal would free travel (no resistance) until it was about a half inch from the floor. The rod is threaded. I just lenghted that until the brakes started to grab at a pedal height I liked. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 12, 2005 Share Posted September 12, 2005 what is the benefit of switching to the ZX master cylinder vs. the stock 240 master cylinder? I wanted to upgrade to toyota 4x4 calipers in the front, but was told by one person I'd need to upgrade the master cylinder, and by another person I'd need to upgrade the booster... which is it? Or is it both? Quote Link to comment Share on other sites More sharing options...
Guest PROJECTRB240SX Posted September 12, 2005 Share Posted September 12, 2005 The Larger Master Cylinder Increases The Amount Of Fluid Pressure In The System Allowing The Use Of Larger Calipers With The Same Effort. If You Use A Stock Master Cylinder In Some Situation It May Not Carry Enough Fluid To Properly Engage The Caliper. The Larger Booster Decreases Pedal Effort By Increasing The Amount Of Vacuum Assitance. I Would Upgrade The Master Cylinder... And If The Pedal Is Too Hard For You, Upgrade The Booster. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted September 12, 2005 Share Posted September 12, 2005 Hey thanks pop N Wood i never knew it was adjustable (i havent opened it up yet, ill check my manual) Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 13, 2005 Share Posted September 13, 2005 too stiff you mean? that's my problem right now, is that the pedal doesn't feel stiff enough to me. I was looking at installing stainless braided soft lines soon to try to remedy this, but you're saying that a larger M/C would also stiffen up the pedal? 280zx M/C bolts right on to the stock 240 booster? Quote Link to comment Share on other sites More sharing options...
RedNeckZ Posted September 13, 2005 Share Posted September 13, 2005 You can use the 280 ZX Cylinder on the 240 Booster. It is a bolt-on. You will have to change the brake lines from front to rear on the cylinder. The 280ZX brake lines are going just backwards compared to the 240Z Cylinder. So you will have to change them around. I just bent mine to fit. Just be careful not to kink them. I have a 1971 240Z and the rod going from the pedal to the cylinder was adjustable. After bleeding them, I adjusted it to what I wanted. I also have the S-12W calibers/300ZX rotors on front and 280ZX brakes on the back. I removed the brake bais switch that is located on the body above the rear diff. on the passenger side. I removed it and bent the line over and re-attached. It made the brakes system a whole lot better. Really helps on those track days. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 13, 2005 Share Posted September 13, 2005 too stiff you mean? that's my problem right now' date=' is that the pedal doesn't feel stiff enough to me. I was looking at installing stainless braided soft lines soon to try to remedy this, but you're saying that a larger M/C would also stiffen up the pedal? 280zx M/C bolts right on to the stock 240 booster?[/quote'] Toy calipers with stock master gives you a pedal that goes 1/3 of the way to the floor before the brakes do much of anything. With a ZX master it is MUCH stiffer. Both the stainless lines and the master will both stiffen the pedal. The master cylinder will do more to stiffen it. A larger master also requires more pedal effort, so you'll have to get used to pushing on the brakes harder to make them work. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 14, 2005 Share Posted September 14, 2005 hmmm... well now I'm not so sure if I want to go with the ZX master or not. I do want a stiffer pedal... and about the toyota brakes things... it seems my pedal already goes 1/3 of the way down before it does anything. I'm not sure if needing to press harder on the pedal to stop would be a good thing or a bad thing... on one hand, it seems this would allow me to better precisely control the amount of braking? So... maybe a good thing. I do NOT like the idea of bending the lines around to switch them though... I've had very bad luck with this '72's old hard lines... they do NOT like moving at all. I've already broken one of my brake hardlines and my fuel return... luckily both ended up being easy fixes, but the hard line going to the M/C definatley would NOT. One more question, if both the ZX M/C and braided brake lines stiffen up the pedal, but the ZX M/C makes it so that you need more braking effort to stop, do the braided lines also make it so that you need more effort? Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted September 14, 2005 Share Posted September 14, 2005 I don't think you will notice much if anything in the way of increased pedal effort from the larger diameter MC. In theory it will require more effort, but in practice it was nothing I noticed. The braided brake lines you absolutely will notice. They take all of the "give" out of the brakes. Once the brakes come on, it is like stepping on a brick. The pedal doesn't move because there are no rubber brake line swelling to take up the excess pressure. Also I didn't really "bend" the hard lines to get the MC to fit. Just kind of rerouted them. The lines have plenty of flex near the MC. If you break a line, then I would question the condition of the lines in the first place. Quote Link to comment Share on other sites More sharing options...
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