SBC_400 Posted July 17, 2003 Share Posted July 17, 2003 I have a 71 240 and I am upgrading the brakes to the toyota 4 piston up front and the zx disks in the rear. from what I understand, it would be better for me to swap the standard 7/8ths MC for the 15/16 ths MC, which is fine because my MC leaks now anyway. but what is involved in the swap? I know it bolts on, but what about the larger piston to fit the 15/16 cylinder, and what about the push rod length? do I need to buy more than just the larger MC? thanks in advance scott Quote Link to comment Share on other sites More sharing options...
jt1 Posted July 17, 2003 Share Posted July 17, 2003 The new MC will already have the piston in it, so no problems there. When I did this sway on my 73, the existing pushrod lenght did fine, but I have seen posts where some people had to adjust it. This may be a model specific deal, since the boosters vary slightly, so maybe someone with a 71 will help out. John Quote Link to comment Share on other sites More sharing options...
Guest z1 performance Posted July 19, 2003 Share Posted July 19, 2003 Along these same lines, I am soon goign to be fitting a big brake kit to my ZX (AP 13.25 inch rotors, AP 4 piston calipers up front, stock disks/cali[pers in teh rear). Is there any need for me to think about an aftermarket master cylinder, or will I be fine wit the stock one? How about the stock proportioning valve? We have used big brake kits extensively on other cars we tune (Supras, 3000GT's, RX7's, Subaru's), and have never ha an issue regardless of the brake kit 9we have used AP< Brembo, Endless and Stoptech), but the ZX is a whole different animal due to its age.. Car is a '79 is that matters...thanks in advance! Adam Quote Link to comment Share on other sites More sharing options...
Guest z1 performance Posted July 23, 2003 Share Posted July 23, 2003 anyone? Quote Link to comment Share on other sites More sharing options...
jt1 Posted July 23, 2003 Share Posted July 23, 2003 Adam, I think you'll be fine with the ZX master, but it really depends on the piston sizes in the calipers. I'm using the 79ZX master with wilwood superlites, 4 x 1.75 pistons, on the front, and wilwood dynalites, 2 x 1.75, on the rear. It works great. I think you'll definetely want a adjustable prop. valve, before I put mine in I had way too much rear brake. John Quote Link to comment Share on other sites More sharing options...
Guest z1 performance Posted July 23, 2003 Share Posted July 23, 2003 Thanks for the heads up - I ended up going with AP5700 calipers, which are 6 piston using Ø27.0mm x Ø31.75mm, Ø38.1mm pistons. I think we'll first be installing it, seeing how it behaves and going from there. Adam Quote Link to comment Share on other sites More sharing options...
jt1 Posted July 23, 2003 Share Posted July 23, 2003 Sounds like a killer setup. Be sure to show us some pics when you get it fabbed up. John Quote Link to comment Share on other sites More sharing options...
Guest z1 performance Posted July 26, 2003 Share Posted July 26, 2003 I promise! Adam Quote Link to comment Share on other sites More sharing options...
Guest billy383Z Posted July 27, 2003 Share Posted July 27, 2003 When I did my brake upgrades, I swapped in the larger ZX 2+2 booster and had to adjust the pushrod length to get the proper pedal height and braking force- it's not a big deal. A little trial and error and about 45 minutes or so and I had everything set up right. I just undid the 2 nuts holding the MC to the booster, pulled it forward an inch or so, and used a pair of vise grips and an 8mm open end wrench to adjust the pushrod length. Push the MC back in place, tighten up the nuts, and try it out. If it needs more (or less, if you can feel the brakes dragging when you try to drive it VERY SLOWLY at first!), repeat the process. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted July 27, 2003 Share Posted July 27, 2003 I put the larger MC in my 70 240. Bolt up deal. The pushrod length was way short, the brake pedal moved without resistance until the last inch of travel. Very simple matter to make the push rod longer so that the pressure started to build within the first inch of pedal travel. Also be careful, the larger MC has the reservoirs reversed from the 240's. Make sure the larger reservoir goes to the front brakes. You need to cross the brake hard lines front to back at the MC. There is enough play in the lines to do this. I think the Arizonia Z car site has info on this. Quote Link to comment Share on other sites More sharing options...
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