1 tuff z

completed changing the master cyl last evening, bench bled it first, bled the brakes-actually took less time that i anticipated. clean fluid, nice firm pedal, took it out for test drive...front brakes still locking. can't get rears to lock. i've [if you've seen earlier posts] removed the wilwood prop valve as well so my system is now is as simple as possible. stock 73 vac booster, zx 15/16" master [with the front & rear lines connected correctly], no factory safety valve or prop valve. any thoughts if i were to swap the lines to the master, ie-connect the front to the rear and rear to front? HELP!!

when u state 'same setup', can i assume that you've also removed both of the factory safety valve [driv fender] and prop valves [firewall]?

clarkspeed & jon, thanks for the continued input. i have noticed greater wear on the fronts. the primary reason that i upgraded the brakes it that i lost mine coming down the front straight at watkins glen [before u ask, i had newly bled system, syn fluid, hi perf front pads, new rear wheel cyl's]-vowing that would never happen again! it was a very interesting experience-hopefully no one on this site will have to go thru. i'm hoping ross will chime in soon and help me out with this delimma. just not safe with the current setup. more info-when i first did this upgrade, i was running dual tilton masters with a balance bar-cable adjusted in cockpit [didn't have enuf rear brakes with that system either, but was better than i have now...]. didn't like the lack of streetability, so i reverted back to the regular old booster & zx master. i have yokohama avs 235.40.17 tires on all 4 corners, custom built compomotive wheels, all tucked under the stock fenders. on pads, i'm not certain what would be the best way to approach this-more bite in the rear or less in the front??

i hear u jon. i was, however, under the impression that when i purchased the 'complete kit' from mm that it would be just that-a complete kit, which i wouldn't have to do much 'fiddling' with...

both front & rear are what ross supplied-kvr performance, i believe they are the carbon/kevlar version.

hey all, have logged some addn'l driving time on the z. now that the reaction disc [rd] is back in place the modulation, overboost/touchiness issues are solved. normal driving the brakes are great-easy to modulate, nice moderate pedal input pressure required for stops and the car doesn't pull, pulsate or otherwise-feels, brakewise, like a normal daily driver. next issue-fronts locking. either from slow speeds [less than 30] or higher speeds [30-70], i can step harder on the pedal and the fronts will lock-seemingly pretty easy. still need to try a more progressive push on the pedal to see how she reacts with that but as of this point i'm more concerned how the car will [or in it's current state-may not] stop in a panic situation. i haven't tried braking higher than 70, yet... my daily driver cars seem to have a shorter stopping distance that my z does now. do i look for a more or less agressive brake pad compound and do it do it for fronts or rears. i emailed ross from modern-motorsports [using the 'contact us' link in their website] over a week ago and still haven't heard back-he's the one i purchased the brake kit from. i'm hoping someone here can help me sort this one out.

it took me about an hour to actually get the booster 'split' apart. the shop manual instructs you to use the special tool-mine consisted of 2 very large screwdrivers. anyway, here's what i did. remove master-leaving the aluminum plate attached to the booster. remove booster, then clamp in vice-clamping on alum plate-use vice jaw protectors or something suitable. use some penetrating lube around the circumference of the seam where the 2 halves join. tap-around the outer portion with a rubber mallet to help 'loosten things up a bit'. then, take the large screwdrivers or levers and position them in a manner that you're attempting to rotate the non-clamped half counter-clockwise. it's a tough nut to initially crack and only needs to turn about 1/16 of a turn. be sure to index mark it first or take pics for reassembly. once turned it simply pulls apart. then it's easy. i called the dealer this morning, they still sell a 'rebuild' kit for it-they're around $100. i believe bonzai still carries the stickers if interested.

rob, that booster is my original. just 90,000 miles on the odometer. i sand blasted it last fall and gave it a quick rattle can paint job. i was pleasently surprised when i 'cracked' it open to see how clean it was. funny, the nissan shop manual recommends that the booster is maintained annually and [used to?] sell a kit to replace the rubber inner workings. wonder how many actually ever did the maintenance?!

sounds like the reaction disc to me. i just went thru the same thing. here's what the disc looks like. http://album.hybridz.org/showphoto.php?photo=7428&cat=500

here's a link to a pic in my gallery [i must b mentally challenged as i can't seem to figure out how to post the pic] showing both the reaction disc and disassembled vacuum booster. reinstalling the reaction disc has solved my overly sensitive brakes and modulation problem. unfortunately i still have too much front brakes-but need to get more drive time-ie-different stopping from various speeds and pedal pressures prior to posting again. anyway for the reaction disc reattachment-my method-clamp the alum plate that the master bolts to in your vice, take two large prybars or screwdrivers on the backside [part that bolts to the firewall] and-after applying some penetrating lube, carefully turn them counter-clockwise about 1/16 turn. mark the alignment position-prior to separating them! i epoxied the disc back in place, cleaned the inside of the booster, inspected all the other parts and reassembled. works great! now looking for another booster to have on hand as a spare. i would absolutely recommend that if you're replacing your master that you remove your booster and as permanently as possible, fix that reaction disc in place! http://album.hybridz.org/showphoto.php?photo=7428&cat=500

looks great, i have been thinking of the same thing for my z. unfortunately it's not made it past the idea stage...

try simply disconnecting the vacuum line first, that should give u a good idea of what the pedal effort would be like.

finished putting the booster in last evening and took a quick drive-brakes feel much better. it was the reaction disc. pesky little bugger. i had to remove the booster then take it apart. i'll post pics on monday of the dissassembled booster and exactly what the disc looks like and how i dealt with it. i absolutely recommend that if you are installing a new master or booster that you remove the booster and adhere the disc so u won't have to go thru this as i did. hopefully i'll get some drive time this weekend and can see if this effected the front/rear bias and what the overall feel is now. did i mention that i love this website?!?! what would i do without u guys!

thanks for the added info jon. to add to my posted question, i do have braided flex lines front & rear. ss hardlines in front, stock steel lines for the rears.

My brake dilemma… My 73 240z brakes are baffling me. Here are my car basics; john’s cars ls1 mounts, t56 trans, r200 3.9 diff with nismo lsd, Autopower 6 pt roll cage, az rear control arms, mike Kelly front adjustables, ground control coilovers & Tokico illumina struts, mm 13†vented front rotors & pbr calipers, mm rear brackets & 11†solid rotors with 240sx calipers-park brake retained, 15/16’s zx master [early one with the separate reservoirs], stock 73 vacuum booster, removed-factory safety valve [driv side frame rail] & prop valve [firewall], custom ss brake lines for fronts to reroute them away from headers. Ok, here’s what my car is doing. Very sensitive pedal, almost like the old gm over boosted systems, very difficult to modulate, fronts lock very easily. I had a wildwood prop valve inline for the rear brakes, but even with it adjusted for max rear pressure still locked fronts easily, removed prop valve-same pedal feel. Disconnected vacuum, brake pedal is much less sensitive but has greater pedal effort-almost too much for the street but tolerable, easier to modulate brakes and they feel much better, still lock fronts before rears. I’ve bled the brakes and master multiple times, nice firm pedal. I’ve also adjusted the rod between the master & booster based on info I found on hybrid [had it too much at one point [locked the brakes and I couldn’t back the car out of the garage!]. no leaks in the system, vacuum booster doesn't make any noise but I’m thinking that either I have a bad component-like the master or booster or…I need to plumb the prop valve inline with the front brakes. i'm leaning toward prop valve for the fronts. Help!

one of my partners is a dedicated car nut, racer and driving instructor. his present & past cars include, yes he has let me [very-enthusiastically:mrgreen:] drive them all but the race car and the newest add to the stable the zo6-porsche 911 porsche club race car, acura nsx, ferrari f355 [he and i ran this and the nsx side by side at 140mph++ one day on the ny state thruway], porsche gt2 club sport [435 hp tt], corvette c6 zo6. took him for a quick ride yesterday in my little hybrid [he had driven it when i had the jcr supercharger setup running] his comments; "dave, your z is incredibly quick, very nice flat and broad torque curve, responsive, sounds great and the install is very clean [thanks to all of u who paved the way and helped to all of my 'what the hell do i do now' questions!] and meticulous, you should be very proud"! told him he needs to get behind the wheel when i have the small stuff completed. needless to say i felt pretty good after hearing that review [drove home with an even bigger grin than usual that day]! still getting used to the comments at the stop lights "what kind of car is that" or even moreso-"what u got in that, it sounds great!" thank you hybrid z! ps-clive [evilc] is coming this weekend to finish pulling parts from his 02 camaro ss, hopefully we can shoot some new video to post soon!

i've pulled 6/8 so far. the toughest were on my 73. soaked the beast, stripped the threads in the puller, new nut for puller-tried again, then stripped the spindle. ok [i'm gonna win this battle!], weld puller to spindle, heat bottom of strut [red hot], beat on one end [with an air chisel] while pulling the other, grunt & groan [the pin and me both] then finally it came out! other side pulled out cleanly with just the puller. go figure... so when do i get my meritz badge...badgez, i don't need no stinkin badgez

the 02's [i believe] don't have an ls6 block, just the ls6 intake. this is true for 01+ f body cars. i did as clive indicated-purchased a totalled 01 trans am ram air ws6. had just 20k on it when smushed. i completely stripped the car and sold all the parts i could. net result was near $0 outlay for the parts i kept-eng, trans, oxy sensors, fans, pcm, battery cables, throttle cables [there are many]. i think a decent donor can be had for a price in the range of $5k-8k, depending on mileage, condition, etc. david

when u see a ref to 'my gallery', you'll then need to do a very small amount of 'finger work'. simply go to the hybrid main page, select 'albums' then once in there 'members galleries' and select the members pics u want to view. they're listed alphabetically or, in my case numerically. i'll do this one for ya. http://album.hybridz.org/showgallery.php?cat=500&ppuser=8104

when i began my swap i had the entire car. while stripping it i kept the factory throttle cable assembly [this consisted of a multi-cable setup which incorporated the cruise control]. anyway, i separated all the parts then combined them together to make one cable. i modified my pedal assembly to accept a cable [ball at the end-like a bicycle brake cable end]. i cut the outer sheath to the proper length then purchased a set screw type end so i could adjust the inner cable length at the throttle plate. if u look in my gallery, the cable is black and to me looks factory. i also retained the gm throttle plate end/mount setup which incorporates a red colored pivoting head-which when u look at it helps to prevent the inner cable from 'sawing' the outer cable when the throttle is worked. if u don't have the donor car, a visit to the local jy should do the trick.

took a trip to where evilc is going to school [alfred university in western, ny] for his senior design project [his 240z-brakes, roll cage, suspension and engine swap]. yes, he's getting college credit for this! figured i'm driving a masters degree [min] with everything i've done to mine. anyway, nice leisurely trip down-about 70 mph cruise around 1900 rpms. before i leave to head home, figured it'd be a good idea to fill up-cause i don't trust the fuel gauge-yet. drove 88 miles, took 2.97 gallons. do the math. told my wife we're getting about 30 mpg, her response, "that doesn't sound right, did u calculate that correctly?". of course i had doubted it too when i first did it in my head but figured it's possible! pretty sure it's accurate, will know better with some more time/miles on the beast. sure has some nice passing power! david

mine is a wilwood as well-7/8" i believe. i then cut off the quick disconnect fitting on the factory slave and tig welded a steel an fitting. then plumbed a flex line from there to the master. pics in my gallery