Here’s Why C8 Corvette Brakes May Pulsate Or Grind
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Eighth-generation C8 Corvette Stingray customers who select the optional Z51 Performance Package may experience occasional brake pulsing or grinding. Now, we’re taking a look at the cause behind this condition, and how to fix it.
Per a report from GM TechLink, some C8 Corvette Stingray models between the 2021 and 2022 model years equipped with the Z51 Performance Package may experience brake pulsing or a grinding noise when applying the brake pedal. Additionally, the brake rotor surface may exhibit pitting. According to the report, these conditions are primarily identified with models that sit for an extended period, particularly in a high-humidity environment.
These brake conditions are the result of brake pad spotting and brake rotor surface grooving. In order to restore brake performance and reduce brake noise, the brakes can be burnished.
The brake burnishing process includes applying medium force to the brake pedal at 60 mph, reducing speed to 30 mph. The deceleration can be repeated 10 times to complete brake burnishing. Note that this brake burnishing process is only recommended for C8 Corvette models equipped with the Z51 Performance Package and associated brakes (RPO code J55), and is not recommended for the JL9 brake system. Refer to the owner’s manual for more information.
As a reminder the C8 Corvette’s Z51 Performance Package includes the following content (relevant RPO codes listed in parentheses):
- Z51 performance brakes (J55)
- Z51 performance suspension (FE3)
- Performance exhaust (NPP)
- Performance rear axle ratio (GM7)
- Electronic Limited Slip Differential (G96)
- Z51 rear spoiler, front splitter (T0A)
- 245/35ZR19 front and 305/30ZR20 rear, blackwall, high performance tires (XFQ)
- Heavy-duty cooling system (V08)
Behind the cabin, the eighth-generation C8 Corvette Stingray is equipped with the naturally aspirated 6.2L V8 LT2 gasoline engine, which is rated 490 horsepower and 465 pound-feet of torque in standard spec, and 495 horsepower and 470 pound-feet of torque when equipped with the optional Performance Exhaust system. Output is routed to the rear wheels through an eight-speed dual-clutch automatic transmission.
Under the body panels, the C8 Corvette rides on the Y2 platform. Corvette production takes place exclusively at the GM Bowling Green Assembly plant in Kentucky.
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The Corvette, and more so with Z51, is a performance car. History would demonstrate such vehicles usually require more attention than easier riding street vehicles. So from time to time to have to accommodate an issue or two in the Z51 in exchange for track ready capability is actually a testament to the extraordinary broad range of performance capabilities built in to this car and we should all be grateful for the designers and technology that has brought us to this point
I had the same issue on my 2014 GMC Terrain.
I got rid of my Chinese sourced original rotors and pads and bought EBC brakes and haven’t had any issues since.
But Im happy GM is using Chinese parts on this “ALL AMERICAN “ sports car !!
Before performing the brake burnishing operation, owners should refer to the owner’s manual. The process in the article incompletely describes step 1 on pages 183 – 184 (2021 version).
I am glad I ordered my 2021 C8 without the Z51 package. I did not want the silly rear spoiler on my car and the drilled holes that come with it in the Z51. I did order the performance exhaust separately. The car runs super cool without Z51 even in Scottsdale Arizona
Any experienced wrench-turner will tell you that brake burnishing (AKA “bedding”) is normal procedure ANY time disc brake pads or rotors are replaced with new. Burnishing brakes is also a very good idea with receipt of ANY new vehicle. When a vehicle is stored outside, even properly burnished brakes will make a grinding noise upon first operation. A light touch of the brake pedal (one time only) is then the only thing needed to eliminate the grinding noise.
Pitting, AKA spalling, or pedal pulsation can take place when improperly burnished brakes are overheated, the driver then stops the vehicle and keeps the brake pedal held (firmly applied) for an extended period of time, the vehicle not allowed to move. Or, could it simply be the end of the Winter season in Bowling Green, could somebody be short-cutting brake burnishing or has Chevrolet chosen material more susceptible to such difficulties? It would be interesting to know.
Exactly. Brake pad spotting with the associated pulsating is not a new phenomenon when cars sit for extended periods in a damp or high humidity environment – or just after washing the car. Certainly, this is less of an issue with asbestos or ceramic pads, but the phenomenon has been around forever, as has the process of burnishing. The Z51 J55 brake system uses semi metallic brake pads – which exacerbates the problem – yet it’s not new.
William you are spot on. Much of the cars today that have the pulse are due to people not burnishing pads to the rotors be it a truck, car or Corvette z51.
This is an important thing few owners and mechanics apply.
Todays pads are lacking many metal fillers that used yo v lean this off and Burnishing toddy has become very important.
The pads today lack the hoods due to all the EPA crap that is removing the things that worked well.
C8.R: You are correct, burnishing (AKA bedding) and material are both very important. As a newbie driver, circa 1970, I vividly recall when my father let me drive his 1966 Belair (283/Powerglide) after he and I installed the first set of asbestos-free aftermarket brake shoes. My first full-effort stop from 65 MPH scared me very, very badly. Terrible brake fade and obviously a much lower coefficient of friction bordering on the dangerous.
Brake materials meeting EPA standards are much better now and brake burnishing has become a must. Actually, I have seen my son salvage several sets of badly pulsing brakes/rotors by overdoing the burnish to the point of making the rotors glow yellow to red at night. Works nearly every time.
Yes so many blame warp when it is lack of burnishing and or rotor thickness variation.
I am just surprised by the rust issue. My two GMC models have the treated rotors that prevent the rust. My truck is a 17 and still no rust.
So, all that money for the car and the Z51 package and people have to play with the brakes? Does Porsche, Ferrari and the other exotics have the same problem? You know what I must be asking too much of GM, really how dare I expect them to build a perfect car!
I know!!!! It’s like they have never built a perfect car in their history.
2000s GM trucks & Corvette *Cough Cough*
But the gullible American consumer will continue to buy up these poorly designed new GM vehicles instead of making a stand like Heroic Ukraine.
🇷🇺🇷🇺🇷🇺🇷🇺🇷🇺🇷🇺🇷🇺🇷🇺🇷🇺 Heroic Ukraine? 🤣 you mean like the war propaganda the ghost of kiev which is not true. We will take the country before the end of the week.
Found the filthy and rotten Russian Bot.
There’s a special place in hell for both you & your buddy Putin.
You don’t even know what a bot is lol. Bots don’t type replies like this, so if your going to say things at least make sure you know what they are ahead of time so you don’t sound like a fool. Also heaven and hell are not real so grow up.
Blah blah blah you Filthy Russian.
Fortunately there’s plenty of room in the ground for your disgusting brothers.
Until the Russian people rise up and overthrow Putin let the body count of Russians rise and rise until they go extinct.
#UkraineStrong
#F%ckRussia
Your not from Ukraine and I bet you have never stepped foot in any Eastern European country.You still have no clue what a bot is. Between the word bot and boomer I would be curious which is the most overused word that people don’t know what it means. I agree the USA is disgusting for how many governments they have tried to overthrow, luckily the bay of pigs and the disgraceful departure from Afghanistan are good reminders of how weak the USA really is.
The United States are mad because we are still in Iraq looking for (WMD) when we could of been the ones to invade Ukraine.
The entire world is mad at Russia. Pay attention.
Your Ignorance is noted though.
Iraq has nothing to do with this.
I’m simply pointing out the irony for a country to say something about another country that has literally done the same thing. The only difference between the two? Western media justified the illegal invasion of Iraq they justified the 2014 coup of the Ukrainian government and they tried to justify the coup in Venezuela but I’ll stop there no need to tell you anymore you can surely figure it out for yourself. Kinda hard to point the finger and say your angry when you occupied a country illegally for 20 years not days years. How many (WMD) did the states find again? I’m waiting for your answer.
I’m a Russian, he’s a Russian, she’s a Russian. We’re all Russians. Wouldn’t you like to be a Russian too?
Or maybe near perfect, really who am I to expect that? Oh and I almost forgot, what about the rear axle defect????
I could reply for my Porsche- nope, don’t have the pitting or the grooving going on 7 years now. And yes I live in the Cleveland Ohio area where salt is used like it is free. However, I had a 2019 Chevy Bolt that I driver all the time using the Regen feature and my brakes were highly grooved and pitted to the point that I started driving it exclusively using brakes and pressing the brake pedal hard when I could. I predict that strong regen in an EV will become a problem. The C8 is a great car and deserves better brake rotors than the crap gm is using.
And don’t forget the ” Market Adjustment”!
Is anyone with the Z51 brake package having a high-pitched squeal under low-speed braking after about 30-45 minutes of driving? The sound is similar to air brakes on a garbage truck.
No noise with mine. Have about 6.5k. Have not done the brake burnishing procedure as have not tracked the car yet. I am based in Seattle with the car in a garage, it is driven a few times a month for the last four months, no sign of rust.
Is yours a Z51 ? The reason I ask is because the Z51 uses semi-metallic brake pads – the base stingray does not. I’m also asking because I have a garaged 2021 Z51, which is currently in “storage” as we are in AZ for the winter. It is also in Seattle.
Yes, it is a Z51. Also in a garage. Not driven in the rain. No rust on the rotors. Dealer has worked on this issue twice. Now, the brake squeal is louder than before. It only squeals after 30-45 minutes of driving and only during low-speed braking.
Yep, Z51, garaged, but has been driven in the rain, washed, driven from BG KY to NC, across to Seattle via Huntsville AL, Pikes Peak, and LA. Great XC road trip machine.
This article states that this is due to “humidity” yes dummy, a brake will rust over when not used. What this article is saying is people are buying these things, leaving them out as lawn ornaments. Just drive them.
I have a 2021 C8 with Z51 and love it. No problems. I can only assume the negative comments come from non-owners.
The people who do not get to play with the other kids.
Reminds me of the guys in Biker gear , that refuse to ride any bike that is not a Harley, but cannot afford a Harley.
All show, dressed up, and no where to go.
I ride any motorcycle, and I will drive any sports car. And waited a year for a new fangled untested Mid Engine C8.
And so glad I did.
The Corvette C8 is a value and a bargain. Much more streetable and refined than numerous other cars
As they say in texas, “All hat and no cattle.”. 😉
“Here’s Why C8 Corvette Brakes May Pulsate Or Grind”.
Inferior materials.
You have information on the materials used? A comparison with aftermarket components would be interesting. Two piece rotors would be a step up from the stock single piece units due to the increased resistance to warping that allowing the rotor to “float” on the hub is good. Larger is almost always better, but going to larger rotors requires larger wheels. The Z06 went that route, and the cost shows this.
It is also interesting that as far as power is concerned, aftermarket has only been able to increase the dyno power <10% over stock with air cleaners, intake manifolds/throttle bodies, and exhaust systems. Doubly so considering that the OEM has to meet all the emissions, extreme environments and sound level codes and rules. Aftermarket can always stick a "for off-road use only" sticker on an item that the user dutifully ignores.
All said, I am impressed with the quality of my C8 and the cost it came in on. As of now it has been an amazing combination of excitement and reliability.
I was speaking to the normally aspirated ground rule. Once one goes to forced induction, the issue becomes structural strength in the short term and accelerated wear in the long term.
The stock clutch pack seems to be good for about 550 ft*lbs (~700 hp @ 6500 rpm). Dodson in NZ sells a stronger unit that is good for better than 800 ft*lbs (>1000 hp @ 6500 rpm has been demonstrated). Folks have been breaking half shafts or the u-joints. After market units are available. It is remarkable that the machine has been holding together through this treatment.
Like a warranty with any of this?
THIS IS A BIG DEAL ABOUT NOTHING
PARK IT INDOORS AND BURNISH IN THE METALLIC BRAKES ON THE Z51, IF YOU HAVE THIS PROBLEM.
THE C8 IS A PERFORMANCE BARGAIN THAT MAKES ALL OTHER MID ENGINED SPORTS CARS LOOK OVER PRICED.
JARED S. LMR IS BUILDING C8s WILL 700+ HP, PROCHARGER ALSO HAS A KIT TO DO THIS, AND LINGENFELTER ALSO HAS ONE.
Mary Barra says GM is the EV leader…
You’d say it too if GM paid you a $20 Million Dollar Bonus for Lying.