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Tech: Z07 Brake Burnishing

 
Old 01-17-2016, 04:57 PM
  #21  
vtknight
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Question - I have just purchased a Z07 with 3000 miles on it. Will general use of the brakes eventually burnish the brakes correctly?
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Old 01-17-2016, 05:05 PM
  #22  
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General use will not require burnishing.

Last edited by hootowlc7; 01-17-2016 at 11:16 PM.
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Old 01-17-2016, 10:32 PM
  #23  
2TallTulip
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general use of brakes will not burnish them.
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Old 01-17-2016, 11:57 PM
  #24  
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Originally Posted by 2TallTulip View Post
general use of brakes will not burnish them.
Thank-you to both responses. My question then is - only in hard track use will you notice a difference in brake performance? Is it dangerous to not burnish them for general use plus some limited track days?

The reason I ask is that they seem to take a serious beating with some people literally blowing up their brakes.
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Old 01-18-2016, 06:33 PM
  #25  
2TallTulip
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you must burnish your cc brakes if you intend to do any track days or aggressive street driving.

if you don't burnish you will not only have sub par brake performance, your pads will disintegrate.

remember, track burnishing is a different/additional step.

when performed properly, burnishing is not a big deal.

i will follow up with my suggestions.
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Old 01-18-2016, 06:58 PM
  #26  
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BEWARE: many people, including me, have cooked their pads by being far too aggressive in street burnishing!

fortunately, i got my original front pads replaced under warranty and learned a few things in the process...


my suggestions on how to burnish:

have a passenger ride along to use a tally counter on their smart phone to count to 50. they can also spot traffic, etc for you.

before you start the process RELAX! adrenaline is your enemy.

turn off active rev match - or it will blip the throttle.

only use first gear.

very gently pull away from a stop - only rev to about 1K rpm (if you ride the clutch it will be damaged).

once clutch is engaged quickly accelerate.

it is easier to watch the tach reach 6K, than the speedo reach 60.

you want to take 7-8 seconds to reach 60mph to stay on the 10 minute schedule to complete.

depress the clutch and brake hard, but not too hard, to a complete stop. i estimate 70-80% of braking capacity.

as the manual states: it should take 4-5 sec to stop. (count to 4-5 out loud).

at stop #25 you should be about 5 min into the procedure. (your passenger can help with this too).

repeat 49 more times.

remember cool down of 60 mph for 5 miles.

owners manual states this process should take about 10 minutes. that's 12 sec per cycle.

my pads started to smoke at stop #15, and at #25 i felt some fade.

also remember, track burnishing is a separate procedure.


again, these are my suggestions. others may have their own technique.
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Old 01-20-2016, 12:06 PM
  #27  
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Originally Posted by 2TallTulip View Post
BEWARE: many people, including me, have cooked their pads by being far too aggressive in street burnishing!

fortunately, i got my original front pads replaced under warranty and learned a few things in the process...


my suggestions on how to burnish:

have a passenger ride along to use a tally counter on their smart phone to count to 50. they can also spot traffic, etc for you.

before you start the process RELAX! adrenaline is your enemy.

turn off active rev match - or it will blip the throttle.

only use first gear.

very gently pull away from a stop - only rev to about 1K rpm (if you ride the clutch it will be damaged).

once clutch is engaged quickly accelerate.

it is easier to watch the tach reach 6K, than the speedo reach 60.

you want to take 7-8 seconds to reach 60mph to stay on the 10 minute schedule to complete.

depress the clutch and brake hard, but not too hard, to a complete stop. i estimate 70-80% of braking capacity.

as the manual states: it should take 4-5 sec to stop. (count to 4-5 out loud).

at stop #25 you should be about 5 min into the procedure. (your passenger can help with this too).

repeat 49 more times.

remember cool down of 60 mph for 5 miles.

owners manual states this process should take about 10 minutes. that's 12 sec per cycle.

my pads started to smoke at stop #15, and at #25 i felt some fade.

also remember, track burnishing is a separate procedure.


again, these are my suggestions. others may have their own technique.
So should you be visually seeing smoke or just smelling them? I have REALLY REALLY BAD squeaky brakes, like plug your ears loud. (6k on the car) I just can't handle it. Dealership said nothing wrong and its normal but it continues to get worse. I tried doing this about 20 times and I could smell the brakes cooking but the squeaking came back 1 day later.
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Old 01-20-2016, 04:11 PM
  #28  
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Originally Posted by John6l6 View Post
So should you be visually seeing smoke or just smelling them? I have REALLY REALLY BAD squeaky brakes, like plug your ears loud. (6k on the car) I just can't handle it. Dealership said nothing wrong and its normal but it continues to get worse. I tried doing this about 20 times and I could smell the brakes cooking but the squeaking came back 1 day later.
Maybe read this article....Burnishing the pads isn't going to do anything to help with squeaky brakes.

https://www.cars.com/articles/2014/0...-thats-not-ok/
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Old 01-20-2016, 04:34 PM
  #29  
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Originally Posted by fleming23 View Post
Maybe read this article....Burnishing the pads isn't going to do anything to help with squeaky brakes.

https://www.cars.com/articles/2014/0...-thats-not-ok/
Well that wasn't very helpful. I already know why they squeak. I am looking for solutions.
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Old 01-20-2016, 06:27 PM
  #30  
2TallTulip
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i recommend a new post asking members about your squeaking carbon ceramic brakes.

have you performed a complete 50 stop burnishing yet?

me and a friend burnished 3 times (3 sets of front pads) and neither of us have had any squeaking issues.

we both have about 5K miles on our cars.
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Old 03-16-2016, 03:22 AM
  #31  
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I just did mine and the entire pad is white, like the others have stated. What is the resolution on this?
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Old 03-16-2016, 09:52 AM
  #32  
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So I followed the directions as closely as possible. I found a long stretch of road, with a high speed limit and no traffic. I did 50; 0-60mph accelerations without wheel spin. Traction control never activated. At approximately 30-35 or so the pedal got really soft. The brakes where smoking a lot. By about 40 the brakes were grabbing nicely. I did the additional 10. I drove in a strait line for about 8 miles to cool them, turned around and drove home. I assumed everything was in order, until I got home. The pads ends are completely white. All the way to the backing, but towards the middle they are the correct color and contrast. The pedal feels very soft. Here are some photos. What are your thoughts?














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Old 08-21-2016, 09:53 PM
  #33  
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Originally Posted by ElCid79 View Post
So I followed the directions as closely as possible. I found a long stretch of road, with a high speed limit and no traffic. I did 50; 0-60mph accelerations without wheel spin. Traction control never activated. At approximately 30-35 or so the pedal got really soft. The brakes where smoking a lot. By about 40 the brakes were grabbing nicely. I did the additional 10. I drove in a strait line for about 8 miles to cool them, turned around and drove home. I assumed everything was in order, until I got home. The pads ends are completely white. All the way to the backing, but towards the middle they are the correct color and contrast. The pedal feels very soft. Here are some photos. What are your thoughts?
I never saw a follow up. How did your pads hold up after this? Crumble immediately? Last well?
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Old 08-24-2016, 12:13 AM
  #34  
ElCid79
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Originally Posted by mxk View Post
I never saw a follow up. How did your pads hold up after this? Crumble immediately? Last well?
4.1 track days and they are still rocking out. Probably one more in them before needing to be replaced. It was NOT an issue. My dealership sent pictures to GM tech about it. Took a few days, and they said they looked good. Obviously this car is pretty heavily front biased, based on wear patterns.

The fluid change took care of the sloppy pedal, and the car is working fantastically.

Last edited by ElCid79; 12-16-2016 at 12:54 AM.
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Old 10-10-2016, 03:42 PM
  #35  
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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?
The street burnishing procedure is to prevent green fade, as described above. Your owners manual also describes a track burnishing procedure, which has you perform a series of 7 or 8 laps at your local road course, and then park the car after a cool-down lap. The first few laps should be done at increasing speed, and the last few should be done at slower and slower speeds.

Why do this? To further season the pads for high-temp use. The street burnishing preps the pads, and is enough for cars that are only driven on the street. But those that see continued high temps (ie, high speeds) at the track will need to perform this procedure after they perform the street one.

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.
Like someone else asked, if anything is damaged, is it covered under warranty since this is in the owners manual?
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Old 10-11-2016, 11:08 AM
  #36  
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Originally Posted by SharkgrayVetteZ06 View Post
Like someone else asked, if anything is damaged, is it covered under warranty since this is in the owners manual?
At 8500 street miles on my ZO7 (never burnished), my brake warning light started coming on periodically after driving for at least 15-20 minutes. Took it to the dealer and kept the engine running with the warning signal still on- after inspection GM told dealer to replace both front pads and front brake sensors (sensors are attached to the pads) at no cost. After installing the pads, dealer did the burnishing per the manual, braking now seems much better than before and no more brake warning light (and no brake dust either). Love these CCB's!
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Old 10-11-2016, 03:05 PM
  #37  
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Originally Posted by nashvegas View Post
At 8500 street miles on my ZO7 (never burnished), my brake warning light started coming on periodically after driving for at least 15-20 minutes. Took it to the dealer and kept the engine running with the warning signal still on- after inspection GM told dealer to replace both front pads and front brake sensors (sensors are attached to the pads) at no cost. After installing the pads, dealer did the burnishing per the manual, braking now seems much better than before and no more brake warning light (and no brake dust either). Love these CCB's!
I guess ill have to find an empty stretch of road really early in the morning I just hope a cop doesn't see me and write me up for reckless driving
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Old 12-08-2016, 04:59 PM
  #38  
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So I guess if my 100% main use of my car is street driving I should do the burnishing? Only thing I will be doing is a 1/2 mile event here and there and some road trips.
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Old 12-16-2016, 12:58 AM
  #39  
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Originally Posted by AZDANZ06 View Post
So I guess if my 100% main use of my car is street driving I should do the burnishing? Only thing I will be doing is a 1/2 mile event here and there and some road trips.
The reason why you burnish your pads is pretty simple. Unburnished brakes create a gas buffer between the pad and the rotor. This can noticeably change your pedal feel under heavy braking even during normal road use.

With that said, everything that I have read and understand about it implies that it does not impact your brake efficacy. Simply press slightly harder, and it will work normally.

The problem is that sometimes people get freaked out by this and release the pedal to to pump it. This is precisely the WRONG course of action in this scenario.

To reiterate the burnishing for street purposes helps with the pedal feel. I would do it.


(I am not a brake engineer, so take everything I said with a grain of salt.)

Last edited by ElCid79; 12-16-2016 at 01:00 AM.
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Old 04-10-2017, 12:02 PM
  #40  
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Updated the original post with new information about Track Burnishing.
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