EMWHYR0HEN Posted November 15, 2006 Share Posted November 15, 2006 I recently changed my stock front calipers to the Toyota 4x4 4-piston calipers. I dinn't have the dinero for the vented, but I did get a pair or clean refurbished calipers from Napa and some new powerslot rotors. I also picked up a set of KVR pads for the front, and changed my rear wheel cylinders because I was having to pump my brakes. Since I had the rear drums off, I got some new carbon metalic shoes, and also changed my stock 7/8 master cylinder to the 15/16 master. I then topped the the new master off with some ATE fliud for my upcoming track event. My first impressions on the street were not that great. The pumping of the brakes was gone, but the overall braking force was weak. The brake pedal was harder than before which I was ok with, However, It seemed like no matter how hard I pressed the pedal, it still had the same over all braking force. I only became more frustrated at the track as I couldnt get the car to stop. I was overheating the fronts badly as they were fading on me. The fronts were definatly working, maybe a bit too hard, so i thought maybe my rears arent helping out. As an attemt to fix it at the track I removed the rear drums so see that about 2 inches of the brake shoe had contact with the drum. I really dont know too much about drums and shoes, but my friends told me that was typical for new shoes. So I put everything back together and drove the rest of the day slow. Bummer. Is the proportioning of the 15/16 ONLY for rear disc? am I supost to wait for me shoes to fully break-in in order to stop correcly? Should I go back to my 7/8 master? right now im really regreting this bake "upgrade" because sadly, I was happier with the stock setup. Quote Link to comment Share on other sites More sharing options...
dsommer Posted November 16, 2006 Share Posted November 16, 2006 I had the same experience, the 4x4 upgrade just doesn't give the braking your looking for. Sounds like you did the install correctly but if you really want to STOP you're going to have to upgrade. Read this, see question #3. http://www.arizonazcar.com/brakekitfaqs.html I promise you the AZ brakes are awsome, you WILL notice a HUGE difference. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted November 16, 2006 Share Posted November 16, 2006 From the FAQ: Question: But I live in Chicago and drive it to work in the winter every day on severely pot holed streets covered with salt. Answer: You're an idiot. and Question: But I live in San Francisco and have to park at the top of a steep hill and go out of town for a month at a time. Answer: Get a brick. That's hilarious! On the subject at hand, you might need a proportioning valve or inspection of the rear brakes. It seems like they might not be working as they're supposed to. Mario Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted November 16, 2006 Author Share Posted November 16, 2006 Dahm, the AZC brake kit is big bucks for a poor college student. I guess if thats the best way to stop, thats the way i'll go. any sugestions on what I should do in the mean time to improve my braking. My rears are working the way their suppost to, I guess their just not working hard enough. what I don't get is why there is a lot of good talk about the 4x4's when their actually not that great. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted November 16, 2006 Share Posted November 16, 2006 You should have gone vented or not at all unfortunately. Even then I heard it isn't that phenomenal, but it should help your fade alot. Anyway, you are lucky. They (Coldffusion and sparky I believe) are making a wilwood install kit to use 12.2" rotors and calipers and such. Basically they supply the hats and caliper brackets and you source pads, rotors, lines yourself. Total cost is projected to be around $500 maybe less. http://forums.hybridz.org/showthread.php?t=113936 Quote Link to comment Share on other sites More sharing options...
mark Posted November 16, 2006 Share Posted November 16, 2006 What pad are you using in your calipers? The pad compound will make all the difference in the world. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 16, 2006 Share Posted November 16, 2006 You need to work on the rears. Manually adjust the shoes so that you feel a light drag as you spin the wheel and tire. You will need to do this after EVERY track session and don't rely on the e-brake to keep the rears adjusted as tight as they need to be for track stuff. Also, new shoes should be contacting the entire drum face, not just 2". Your friend is mistaken. Did you get the drums surfaced? Its also very important to bed the brake pads and shoes properly before using them hard. The pad supplier should have included bedding instructions, if not check the StopTech site for proper pad bedding. Did you change out the brake fluid? If you're going to do track days, replace ALL of your brake fluid with Motul RBF600, ATE 600, or Ford Heavy Duty truck brake fluid if you're on a budget. Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 16, 2006 Share Posted November 16, 2006 I went through what you are dealing with... track use on stock disks is NOT ACCEPTABLE... I fought with them for a long time... I'm knuckle headed... I added multiple cooling ducts and a modified backing plate, ATE fluid, freshly rebuilt everything... you can buy higher temp pads compounds... but then you will start burning caliper seals and cracking disks... I finally gave up and installed a set of spacers, 1984 300zx 4 lug rotors, and the later, larger model Toyota calipers... It was instant bliss!!!! Ohh btw... the 1990s Z32 front pads fit the largest Toyota calipers... so pads are a dime a dozen..... ----------------------------------------------------------------------- I am using front Toyota vented disks, rear drum brakes, stock master cylinder, stainless lines, stock 72 proportioning valve.... My current issue is that the rear brakes just don't do enough without custom high friction shoes... they are EXPENSIVE!!! nearly $200 with shipping... I am sick and tired of that money pit... For my last few events I have been using a more affordable "performance" metallic compound and it is as slick as teflon... the damn rear drums don't even get hot... they are not doing a damn thing... The cost of relining the rear shoes is enough for me to give them a big thumbs down 1 Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted November 16, 2006 Author Share Posted November 16, 2006 John- Thanks for you input. The shoes were properly ajusted. They had slight drag on them. However, I didn't resurface the drum before I installed the new shoes. I put the shoe inside the drum to make sure it was a sure fit, and the drum didnt have any lines or imperfections. any Idea on why the entire shoe surface isnt contacting the drum? i'll look into bedding the shoes. Bjhines - i'm glad i'm not alone on this. At the track my rotors were blue and I wouldnt dare to touch them, but i was able to hold onto the drums and shoes right away. Sad, I guess I should have gone disc instead of trying to mess with the drums. By the way, the 300zx Z32 pad your using, is it from an NA z32 or tt? I used to have a 240sx and I upgraded it with Z32 TT calipers. I remember the TT calipers were bigger than the NA's. I was very impressed with the stopping of my 240sx, If your current setup with the vented Toyota brakes is somewhat similar size to the Z32 fronts, i'll have to look into doing the vented setup, or wilwoods.... Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 16, 2006 Share Posted November 16, 2006 I would say that eventually you will wind up spending the same amount of money/time on brakes within a dozen events... no matter which way you go... the factory type conversions are nearly as expensive as the Willwoods... Willwoods have cheaper pads available and they are brand new units... Brake friction materials have come a LONNNGGGG way since the Z cars were originally raced... you can pick and choose pad materials to proportion your brakes... I can really throw out the anchor when I get them biased for track conditions... The easiest upgrade for those of us not limited with brake modifications... is exactly what I have done... except the expense and custom relining nature of the rear shoes... The rear drums cool almost too well... I would bet that the cast iron drums would work more consistently that the composite aluminum drums that came on the 240Zs... The real issue I have with the rear drums is the lack of consistency and the 2-step pedal feel in street use... I don't notice it on track at all... Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted November 17, 2006 Author Share Posted November 17, 2006 The real issue I have with the rear drums is the lack of consistency and the 2-step pedal feel in street use... I don't notice it on track at all... Hah, I know EXACTLY what your talking about. Maybe its because we just mash on them at the track. I see you wipers are moving up also, I take them off cuz is hard for me to see the apex's when you sit so low and the wipers move up, lol. Thanks. Quote Link to comment Share on other sites More sharing options...
z-ya Posted November 17, 2006 Share Posted November 17, 2006 If you are using the 4x4 calipers with the stock rear drums, the 7/8" MC is what you want. I run this exact setup, with the stock proportioning valve on my time trial car, and the brakes are ecellent. The 15/16" MC will require too much pedal effort. On my Wife's 78' 280Z, I also have the same setup, and the brakes are also excellent. A few things to try: - Put your 7/8" MC back in there - Make sure the rear drum brakes are adjusted properly. This can have a huge effect on pedal feel. On my time trial car I adjust the drums after each session to keep the pedal firm. Hope this helps Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted November 17, 2006 Share Posted November 17, 2006 johnc touched on this. A proper bedding cycle for the rotors pads and shoes is a MUST. I use the technique posted on the Baer Brakes website. Go to the tech section. http://www.baer.com/ Quote Link to comment Share on other sites More sharing options...
Team Zleep Posted November 17, 2006 Share Posted November 17, 2006 i did new rotors and the smaller 4x4 calipers. just as Z-ya said... 7/8 MC, adjusting the rear drums, and a good system bleeding, and my breakes are freakin awesome!! i've never really had a problem with them, and ive been mashing on them hard for the past... 2 years or so. i'd trust it with a track day. well i need to bleed them again...ugh. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 17, 2006 Share Posted November 17, 2006 well i need to bleed them again...ugh.Try a set of speed bleeders. http://www.speedbleeder.com/ Totally changes the level of effort to bleed the brakes. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 17, 2006 Share Posted November 17, 2006 The Toyota 4 piston calipers and 280ZX rear disc setup was fine for me until I added slicks. Then I think I was able to put enough heat in them that they just weren't up to the task. I think your problems are that your bias is too far to the front and the rear shoes need to be recurved or maybe replace the drums, then the rears need adjusting. Good luck finding a shop to recurve the shoes... Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted November 18, 2006 Author Share Posted November 18, 2006 If you are using the 4x4 calipers with the stock rear drums, the 7/8" MC is what you want. I run this exact setup, with the stock proportioning valve on my time trial car, and the brakes are ecellent. The 15/16" MC will require too much pedal effort. On my Wife's 78' 280Z, I also have the same setup, and the brakes are also excellent. A few things to try: - Put your 7/8" MC back in there - Make sure the rear drum brakes are adjusted properly. This can have a huge effect on pedal feel. On my time trial car I adjust the drums after each session to keep the pedal firm. Hope this helps Thanks Z -ya. I think your right about putting on the stock 7/8 master. I think the 15/16 master is better suited for the rear disc setup. I'm guessing the F/R proportioning is alot different between the 7/8 and 15/16 master cylinders. Also, I just put back on my old rear shoes, ajusted them and drove it for a while. Then I pulled the drums off and noticed that 100% of the shoes had contact with the drum. I guess if I want to run the new shoes I'll have to resurface the drums and bedd the shoes. Quote Link to comment Share on other sites More sharing options...
Team Zleep Posted November 18, 2006 Share Posted November 18, 2006 Try a set of speed bleeders. http://www.speedbleeder.com/ Totally changes the level of effort to bleed the brakes. it's like the holy grail of brake bleeding!!!!!! what's your experience with them??? im buying a set A.S.A.P! Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 18, 2006 Share Posted November 18, 2006 With the speed bleeders, just put the hose on the nipple, crack the bleeder about 1/4 turn, and then pump the brake pedal a few times. I usually use my hand on the pedal from outside the car so I can watch the fluid come out. Just be careful to refill the resevoir before you run out and have to start over It's that easy. BTW, if you don't have access to surgical tubing, get it from speed bleeders. It seals a lot better than the harder clear PVC I had been using from the hardware store. Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 18, 2006 Share Posted November 18, 2006 Well the problem with speed bleeders and any of the suction devices is that the bleeder nipple threads do not seal very well... You can put all the check valves in them you want... the threads will still let air by.. I think the speed bleeders are a waste of time... I have aquired them on past cars and ended up throwing them in the trash after I found that the various parts in them had corroded after a few seasons and gone to complete shiat... they wouldn't evn allow fluid to flow... ======================================================== ONE of the proper ways to bleed brakes is with 2 people.. one on the pedal and the other on the wrench... the wrench man always closes the bleeder before the pedal pusher stops pushing... that does not allow air into the system... That is the classic method... The other way to do it is with a pressure feed on the master cylinder cup... there are lots of systems designed this way... they are typically around $60 for a professional model... the trick is... It is only a GD pesticide sprayer... get the smallest cheapest model at your hardware store.. $10... drill a hole in an old master cylinder cap to attach a hose... put a few ounces of brake fluid into the sprayer and push it through the system... A few pumps on the handle will flow fluid continuously until you close the bleeder... then you just move to the next bleeder and open it until you are satisfied it is bled... you usually won't have to pump the sprayer more than once at the beginning of the session... The neat thing here is ... you wont ever have to add fluid... just make sure there is fluid up to the low mark... the pressure bleeder will add fluid as it displaced fluid out of the bleeder nipples... as long as you have a positive seal around the MC cap... you won't overfill the resivoir... god forbid should you get that part wrong... it will make a mess if you don't get a good seal there... and I know some of you are thinking... they put a "special" thread sealant on teh speed bleeders... Yea... for ONE or possibly TWO bleeding sessions it will seal... realatively well... then it just falls apart... and then it is just another mess on the threads that needs to be cleaned off... and then the threads don't seal anymore.. and then the speed bleeders don't do one damn bit of good... those things are a farce... Quote Link to comment Share on other sites More sharing options...
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