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Tech: Z07 Brake Burnishing

 
Old 05-04-2017, 01:33 AM
  #41  
Dabigsnake
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Originally Posted by jvp View Post
Updated the original post with new information about Track Burnishing.
Thanks, jvp
I did the street and track burnishing according to the manual, but my front pads seemed to separate from the backing, after only 3500 miles with around 4 hard, (15 min) track sessions and another 4-5 medium sessions (not days, 15 min sessions). Since I see this updated burnishing info, and the fact that the original front pads have been discontinued, I am hoping my deal replaces my front pads. It's at the dealer now, with a clicking noise, and a bad AC compressor. Seems I may have cooked all the solvent out of the entire pad causing the bonding agent to release too far back on the pad, by the backing plate?
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Old 05-04-2017, 06:13 AM
  #42  
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Originally Posted by Dabigsnake View Post
Seems I may have cooked all the solvent out of the entire pad causing the bonding agent to release too far back on the pad, by the backing plate?
Nope. Not unless the entire pad is white. Something else happened to that set of pads, but I don't know what.
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Old 05-04-2017, 01:34 PM
  #43  
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Dabigsnake commented that the old pads are discontinued? can you confirm.

also, where can i read the entire commentary from Chevy on the updated cc brakes burnishing?

thanks.
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Old 05-04-2017, 03:17 PM
  #44  
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Originally Posted by 2TallTulip View Post
Dabigsnake commented that the old pads are discontinued? can you confirm.

also, where can i read the entire commentary from Chevy on the updated cc brakes burnishing?

thanks.
old GM number is 23198733, every online site shows discontinued.
old AC Delco # is 171-1142- not available

New AC Delco # 1711186 I found on Amazon for $446, now showing $450. Much cheaper than Dealer quote of $1055 fronts.

Sorry I did not bother w getting new GM number from dealer.

commentary? see the first post here where jvp changed the burnishing procedure April 10th. I believe there is a reason. My dealer has told me that GM will not cover new pads!! That's nuts when I see others with 8500 miles on their car getting new pads. one of my sensors had burned through the clip, but the loop was intact just hanging? no message light either.?? I'm not happy, and will push for GM approval of pads.




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Old 05-04-2017, 03:29 PM
  #45  
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Originally Posted by jvp View Post
Updated the original post with new information about Track Burnishing.
can you speculate of the reasoning behind this change? Thanks
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Old 05-04-2017, 04:33 PM
  #46  
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I've just purchased a Z06 with Z07 package and checked the forum after reading the burnishing break-in ......... it'll take me a fair time to first put 1,000 miles on it before performing the burnishing, which will give me time to find a quiet 10 mile stretch of road.
So if I'm understanding this correctly the purpose of the burnish procedure is to evacuate the bonding out-gasing from the pads, its has nothing to do with the discs, whether steel or carbon ceramic, correct?
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Old 05-08-2017, 11:14 AM
  #47  
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Originally Posted by jvp View Post
(re-posted from C6 ZR1 section as it still applies).

Why do I have to burnish the brake pads in my new ZR1 or Z07-equipped Z06?

Pad Burnishing
The pad material that's attached to the pad backing is made by pouring a slurry of muck into a mold and letting it set. That slurry of muck includes a bonding agent, or glue of sorts. That agent needs to be there, but it will cause a problem if the pads get overly hot.

When a non-burnished pad gets hot (I don't know the exact temp), the bonding agent will begin to out-gas and boil off. What happens with that gas is that it forms a barrier between the pad and the rotor. An air cushion of sorts. And an air pocket pressing against a spinning rotor is not as effective at stopping the car as a pad pressing against it.

The driver experiencing this will note that the pedal will get somewhat soft and resist slightly when they try to slow the car down. Simply pressing the pedal harder will force the air pocket to evacuate, and the pad will then come into contact with the rotor.

This unsettling feeling is called green fade. It feels like the pad is fading, but it isn't. The car will stop, but it takes a harder pedal press to make that happen.

Thus the burnishing procedure. The stops in question need to be done sans ABS, ie threshold braking the car, so that a constant pressure is kept on the pad during the stop. This is to help build up the heat in the pad. The goal here is to bake off the top layer of bonding agent from the pad so that an air pocket forming becomes impossible or highly unlikely.

GM has determined that, on average, it takes 50 60-0 stops in 10 minutes' time to get the pads hot enough for that. Basically what you're looking for is the pad to start fading bad during the procedure. That generally happens around stop 40 or so, when braking distances feel like they're increasing dramatically. Once this point has hit, the gasses are beginning to boil off. A few more stops after that point and the brakes will feel like they're grabbing before you even touch the pedal. At that point: you're done. Drive the car for a while at legal speeds to cool the pads.

Why not bake ALL of the bonding agent out? Well, if you do that, the entire pad will fall apart. That's not a good idea, right? Instead, the pad will continue to slowly boil off the rest of the bonding agent over time as you wear the pad down. You'll never notice it happening though.

How do I know I've done it right?
As described in the owners manual, once you've correctly burnished the pads, you'll see a white outline around the edge of the pad, right where it meets the rotor. It'll look something like this:





What's the track burnishing procedure for?
Editor note: This part of the post has been updated on 10 April, 2017. New information from GM.
Previously, it was thought by GM that the track burnishing should be done AFTER the street burnishing, IF you intend to drive on the race track. Earlier ZR1 owners manuals called for street burnishing then track burnishing. However, this is no longer required through testing by GM. When they send their new cars to the track, they only track burnish them.

So what does that mean? Following the owners manual, drive seven or eight laps with increasing speeds and then decreasing speeds. The middle lap should be full speed or near to it. Once you've completed those laps, do a final lap or two as a cool down, using your brakes as little as possible, and then park the car for the rest of that session. That should burnish the pads properly for use on the track (and on the street!)

But I never drive my car really fast. Do I need to do the burnishing?
There's a lot of miss-information out there that the street burnishing procedure only needs to be performed if you're going to race or track your car. That statement needs to clarified carefully, to: if ALL you do is drive your car on the street and highways at legal speeds and NEVER intend to carve canyons, drive quickly up or down a mountain road, or perform high-speed runs (legal or otherwise), then you don't need to perform the burnishing. However, if there's even a remote possibility that you will do any of those things, it'd behoove you to at least perform the street burnishing.

Failing to do that with pads that get heated up will likely result in green fade, and a very uncomfortable driver.

So if I'm understanding this correctly the purpose of the burnishing procedure is to evacuate the bonding out-gasing from the pads by developing sufficient heat for the reaction, it has nothing to do with the discs, whether steel or carbon ceramic, correct?
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Old 05-15-2017, 12:37 PM
  #48  
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Great info. Same issue. I got through about 35 60 to 5's in the middle of nowhere and traffic got all over me. Had some burnish signs. Did a serious track day and pads are well burished with a soft pedal. Dealer charged me for DOT 4 but looks like they just took the cash.
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Old 05-15-2017, 06:50 PM
  #49  
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Originally Posted by jvp View Post
Nope. Not unless the entire pad is white. Something else happened to that set of pads, but I don't know what.
GM Service said too bad. No help coming my way. I'm not happy and would really except a good explanation for the discontinued pads, rather than the $ or even a new set for free. and what about the change in burnishing procedures? They do this stuff for a reason, right? Yes, I drive it hard, but I paid the big bucks for that right.




They were burnished properly, but seemed to start coming apart and crumbling off?







What does this tell ya. I must have done a slow cool down lap? kinda weird. 3.7 mpg is about right when on track, but 38mph average. Took 6 gals to run 23 miles. That's about $5 a lap in fuel cost w 100 oct.



Got no message cause sensor wire was still intact, but just hanging lose?
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Old 05-17-2017, 01:41 AM
  #50  
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Is there a new part number for the Z07 rear pads, or still GM Part No. 23198750 (ACDelco 171-1143)?

Last edited by Hit Apex; 05-17-2017 at 01:59 AM.
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Old 05-17-2017, 11:50 AM
  #51  
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U


The latest for 07 CCB



Latest part numbers, since other part number discontinued.
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Old 05-17-2017, 11:58 AM
  #52  
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Originally Posted by Dabigsnake View Post
U


The latest for 07 CCB



Latest part numbers, since other part number discontinued.
Those are just the fronts right? What about rear part numbers?
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Old 05-17-2017, 12:00 PM
  #53  
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This is the ZR1 pads. These seem to be the same fit, but different #. Would love to know which ones are best for track use only. Or?


ZR1 front pads. ?? Difference from Z07 pads?
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Old 05-17-2017, 12:07 PM
  #54  
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Originally Posted by Hit Apex View Post
Those are just the fronts right? What about rear part numbers?
Rear part number has not been discontinued I believe the rear pads are
GM # 23198750, and Delco # 171-1143
FYI- (Old discontinued fronts were GM # 23198733, Delco # 171-1142)
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Old 05-17-2017, 12:32 PM
  #55  
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Originally Posted by Dabigsnake View Post
Rear part number has not been discontinued I believe the rear pads are
GM # 23198750, and Delco # 171-1143
FYI- (Old discontinued fronts were GM # 23198733, Delco # 171-1142)
Got it. Makes sense. Thanks!
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Old 05-20-2017, 07:46 PM
  #56  
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Update::: My pads failed like Snakes... Delaminated, just as his did...
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Old 05-21-2017, 12:19 AM
  #57  
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Originally Posted by ElCid79 View Post
Update::: My pads failed like Snakes... Delaminated, just as his did...
Details? Pics? What straight-away speeds are you braking from?
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Old 05-30-2017, 08:22 PM
  #58  
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i will be back on the track (Autobahn in illinois) next week with brand new front cc pads. i apologize if it seems like we are sawing brake dust.

can you confidently say that skipping street burnishing and following the track burnishing procedure is an acceptable way to prep my new pads?

thank you.
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Old 05-30-2017, 11:13 PM
  #59  
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Originally Posted by Dabigsnake View Post
Details? Pics? What straight-away speeds are you braking from?
Roughly 150. I am not sure that I still have any pictures. I caught my issue well before they developed to that point. I was getting an odd brake sound, pulled the pads and they were just starting to separate. My pads however, were not nearly as worn as his.
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Old 05-31-2017, 12:07 AM
  #60  
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I have about 8k miles on my car now a year later, should or can I still do this? I have seen some after pictures here that do not excite me but I feel like I should still do it? Please advise. Thanks
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