Rob Posted February 18, 2001 Share Posted February 18, 2001 Does anyone know the proper way to break in new rotors? No punn intended! I know I don't, cuz I followed the procedure on the Hawk brake pad burnishing procedure, which states specifically that it applies to new and used rotors, and I cracked both rotors!!!! I guess its possible there was a casting problem but I think I put too much heat into them too fast. Not good! Be careful out there people! Hope I don't get in trouble here- my problem was not on my Z car but my RX-7. This is the best car tech site I've ever found and I think my concern applies to all cars. Thank God my new rotors didn't crack on the Z when I installed them with the wilwoods! Yep, I still have the V8 Z and don't plan to get rid of it! Too much fun! Thanks! Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted February 18, 2001 Share Posted February 18, 2001 is it cold there?were those new rotors from same batch?all i can think of is to use a torque wrench to install wheels.and torque rotors to hubs. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted February 18, 2001 Share Posted February 18, 2001 Crossdrilled or anything? Man, I feel for you. I don't look forward to replacing my 7's rotors. Crossdrilled like Swiss cheese but with ABS it hauls that puppy down hard! I'd love to have ABS on the Z... Quote Link to comment Share on other sites More sharing options...
Rob Posted February 18, 2001 Author Share Posted February 18, 2001 No, they are not cross drilled or anything. They are Raybestes brand which I thought was supposed to be a good brand. The temp was about 45 probably. The wheels were torqued to 55 lbs, and on this car the hub and rotor are all one casting. (which makes changing them much more fun, all that grease and press fit bearing races and all!) The rotors were probably not from the same batch. I've been having too much fun with this project. The first pair I received had the bore for the inner race out of tolerance so I returned that one and they had to special order the replacement. Thanks for the comments. [This message has been edited by Rob (edited February 18, 2001).] Quote Link to comment Share on other sites More sharing options...
DavyZ Posted February 18, 2001 Share Posted February 18, 2001 Drewz, your car looks wicked with the tunnel rammed TBI set up. Is that thing streetable and how does it work? Quote Link to comment Share on other sites More sharing options...
Ray Posted February 19, 2001 Share Posted February 19, 2001 Take them back.... It may have been a while since you bought them but I would take them back. If the place you bought them won't warenty them call the mfg... If they say no be a jerk, Remember this is a safety item... If the mfg rep is smart he will replace them... Ps..and don't tell them about the pads. Quote Link to comment Share on other sites More sharing options...
Rob Posted February 19, 2001 Author Share Posted February 19, 2001 Yes I did wash the rotors thoroughly. I installed the pads correctly. The bearing play I set according to Haynes for Zs. It consists of tightening to 22 ft lbs and backing off 60 degrees, all the while rotating the hub. I didn't feel comfortable with the Mazda procedure which said to tighten the nut until the hub binds and then backing off 1/6 turn. Seems kind of subjective. Funny you should mention the pads. That's the first thing the guy asked was what pads I was using. I admitted that they were Hawk pads. He asked if they are racing pads and I answered with "well they are performance pads". I think I learned that one from Clinton. The 100% honest answer would have been "hell yes they are racing pads, and I still want you to replace those rotors, please". His stance was that if they were metallic he wouldn't warranty the rotors because his information stated that this car should only have organic pads. Well I brought one in and we agreed that they were probably carbon metallic, which I actually wasn't sure about. Makes sense now I think about it since Hawk calls it Ferro Carbon. Ferro for ferus or iron I guess. I stood around for a while, and next thing you know he said that he would replace them for me this one time. I will be calling Hawk to see what they have to say about this. If they hadn't have put those instructions in with the pads I would have never put that much heat into the rotors right off the bat. By the way if you are interested the Hawk procedure is as follows: (no I am not recommending this!!) If using new or used rotors you must follow the steps listed below to achieve maximum brake performance. 1. slowly engage brakes 6-8 times at medium speeds. Don't drag brakes or come to a complete stop. 2. Increase speeds to simulate race conditions. I used 75 mph which should be very conservative I thought. Allow 6-8 Very Hard stops at racing speeds. 3. Allow brakes to cool for 15 minutes or more by parking the car. I actually heard them pop on stop number 6. The right was within one second of the left which was amazing to me. That would take very identical rotor characteristics and very balanced heat being generated on each side. Or, perhaps very balanced bad luck. Thanks for all your inputs. Be careful if you get new rotors and or race pads! Drewz procedure would have worked fine I'm sure. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted February 19, 2001 Share Posted February 19, 2001 I feel your pain, man! Hope you are successful next time around! Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted February 19, 2001 Share Posted February 19, 2001 This all depends on the type of pad you are using. Did you wash the rotors before you installed them? Did you ensure proper fit of the pads and pins? How did you tighten and set the bering play? Some pads take a 20 minute breakin drive with slow gradual stops to set the pad and rotor. Others are not as fussy. I usually take a vehicle I have done brakes on for a 5 minute drive with the first 5 stops being slow gradual complete stops. Than I will perform a quicker stop from 100 kmph to see if there is any unevenness in the rotors by feeling for any brake pedal pulsation. If there is none I do some quicker stops to finish the drive. P.S. I am an ASE. certified mechanic and this is according to Raybestos and GM specs. Hope this helps you may want to contact the area rep. if this happens again ------------------ The only stupid question is one you wanted to ask but never did!!! http://ca.photos.yahoo.com/andrewzcars Drewz Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted February 20, 2001 Share Posted February 20, 2001 The closest I've come to "racing" pads were the ones that came with the Cobra brakes I put on the Mustang. I don't think I'd EVER want something more aggressive than that for the street driving I do. The first 4 or 5 stops on a cool morning were eye openers. I've got a short steep hill just out of my driveway with a stop sign at the bottom - on cold mornings this was a real thrill! Apply brakes - nothing happening, apply harder - a little better, stand on it hard - Whoa horsie! No thanks The neat metallic grinding sound I've heard from some "race brakes" is something I'd want to do without as well. Really aggressive pads eat rotors until they reach operating temps - yikes! Hrm, will you be using these on the street? Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted February 20, 2001 Share Posted February 20, 2001 Yes that car is very streetable as I drove it for 4 months every day non-stop. As far as racing pads I can find part numbers if you are using the toyota caliper setup. They are not for the meek at heart since they need to be at a certain operating temp. before they work well or at all in some applications. ------------------ The only stupid question is one you wanted to ask but never did!!! http://ca.photos.yahoo.com/andrewzcars Drewz Quote Link to comment Share on other sites More sharing options...
Rob Posted February 20, 2001 Author Share Posted February 20, 2001 Mainly I will be using it for road racing. However since I can't afford a trailer this year I will be driving it to the track. I've done some more research on these pads, and they will turn the rotors down like a lathe until they warm up. The Hawk rep told me I should swap the race pads for stock pads just to drive to the event, or to autocross. Gee, that's convenient! Quote Link to comment Share on other sites More sharing options...
Guest scca Posted February 20, 2001 Share Posted February 20, 2001 the hardest pad that should be used on the street is the HPS +, any nigher COF (coef.of friction) just wont work on the street,,,,,,, as others have said cold stops-- what cold stop.. my race car takes 3 full laps to warm up the hawk pads to operatin temp. lap one turn one after a pace lap is exciting to say the least. the rep was correct in tellin you that you should drive there with street pads and then change to a rougher compund.. time for larger rotors! mazda's are notorious for cracking rotors.. they cant take high heat-- as you learned ------------------ Mike mike@fonebooth.com http://www.fonebooth.com/brakes.html raceparts and brake upgrades. Quote Link to comment Share on other sites More sharing options...
Rob Posted February 21, 2001 Author Share Posted February 21, 2001 Unfortunately, I can't go to larger rotors. It is a spec class and you can't change much at all besides suspension and cage, and for that they tell you exactly what is allowed, brand, model number, everything. Guess I'll just have to get really fast about changing pads. Since you seem to know something about brake pads, I've got a question for you about pads for my Z with Wilwoods. What do you think of Polymatrix "C" compound? Its a lower friction race pad. I'm wanting to use that one as an all around do all pad. However I'm learning that a do all pad really doesn't exist. Curently I have polymatrix "cold stoppers" and I have two issues: fade and too much grab before they start to fade. Its way too easy to lock a front tire up. I just found out that the guy that sold me the brake kit put cold stoppers in it, and its no wonder I don't like them, they are pretty much a drag car pad, and Polymatrix refers to them as "sticky". Quote Link to comment Share on other sites More sharing options...
Guest scca Posted February 21, 2001 Share Posted February 21, 2001 have you tried hawk? their HPS+ is a good pad.. i run black/blue depending on the track. iknow a few rx7 (1st gen) that use the blues but not a street car..too.. i do know that a few rx guys replace their rotors at least 2x a year... mine last 2 seasons.... thats one issue with spec... Mike Quote Link to comment Share on other sites More sharing options...
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