Who else has had warped rotors?

[Mach_Tuck]

Yes I have never had problems with warranty work kia. But all the work they did on this car especially track time you think the brake problem would have came up. Maybe we are doing something wrong who knows.

I would imagine that 99% of the cars being used by customers are NOT being driven like the cars on the Nurburgring during testing...mine is at 2.3K and now will be looking for this issue as well.

I am not so confident in my dealers ability on warranty work yet as i brought in my GT2 for a headlight adjust and was turned away with the response, "we dont know how to do that." Five days later and still waiting for them to figure out. Second dealer i called said, that he has "never heard of anyone complaining of such a thing" and asked "if i was sure they were pointed incorrectly"

Time will tell on lots of items here.

My fear with these Brembos is that they were specifically designed for Kia so not a "tried and true" off the shelf unit from Brembo. At least, this is what they told me at the Kia Stinger Experience when i asked about the brakes. Ive also noticed that "KIA" is stamped into the caliper so this seems to hold correct in my opinion.

Turning rotors at 3K miles is just asinine. I am curious how close they are to min thickness after this. Making them thinner will only cause warp easier as well.

 

[BrianAx]

I would imagine that 99% of the cars being used by customers are NOT being driven like the cars on the Nurburgring during testing...mine is at 2.3K and now will be looking for this issue as well.

I do find it odd that no one had mentioned that "rotor warp" feel can come from the lug nuts on the wheel being over torqued past specs - which can cause the rotor to warp over time... food for thought...

 

[DiabloStinger]

FYI, if you are feeling a pulsation without applying your brakes it isn't the brakes.

 

[Waynerm002]

You guys must be braking very hard from some excessive speeds to warp those rotors. When I was younger I did that on a few cars, as I got older, I pay more attention and downshift manually when I can to slow the car while applying the brakes. I cooked my brakes once, ran into an intersection at a "T" junction and almost off the road. Since that experience, I typically replace the pads and rotors along with getting stickier tires. I have since started braking earlier with downshifting to bleed off the speed and have not warped any since.

I feel I still drive relatively hard but I never warped the brakes on our Volvo S60 R Design but my wife did so after a few months of driving it. I drove with her and saw how she drives. She speeds up to follow traffic to not leave too much space for another vehicle to come in and then have to brake hard when the vehicle ahead brakes. She got one warranty replacement of the rotors from Volvo when we took it in for service due to it "making a lot of noise". She wore those things down and didn't know why the car was making noise, lol! I think this is more on how folks drive than KIA not using quality parts on the Stinger. Of course, you can spend the money on better braking components, like I used to, just to offset these issues, based on how hard you are on the vehicle. There a re a lot of good info on how to prevent this in this thread. Be safe out there folks!

 

[Mach_Tuck]

You guys must be braking very hard from some excessive speeds to warp those rotors. When I was younger I did that on a few cars, as I got older, I pay more attention and downshift manually when I can to slow the car while applying the brakes. I cooked my brakes once, ran into an intersection at a "T" junction and almost off the road. Since that experience, I typically replace the pads and rotors along with getting stickier tires. I have since started braking earlier with downshifting to bleed off the speed and have not warped any since.

I feel I still drive relatively hard but I never warped the brakes on our Volvo S60 R Design but my wife did so after a few months of driving it. I drove with her and saw how she drives. She speeds up to follow traffic to not leave too much space for another vehicle to come in and then have to brake hard when the vehicle ahead brakes. She got one warranty replacement of the rotors from Volvo when we took it in for service due to it "making a lot of noise". She wore those things down and didn't know why the car was making noise, lol! I think this is more on how folks drive than KIA not using quality parts on the Stinger. Of course, you can spend the money on better braking components, like I used to, just to offset these issues, based on how hard you are on the vehicle. There a re a lot of good info on how to prevent this in this thread. Be safe out there folks!

I would tend to agree with this. however, many are saying they are merely "daily driving" the cars. Warping a rotor with less than 3K is quite a feat. Time will tell i suppose. My only concern, as stated earlier, is that this a new "product line" for Brembo specific for Kia and may not hold the pedigree of its other product lines

 

[Helo58]

It is really hard for me to believe that any modern Brembo would "warp." Typically it is pad material "melted" to the rotor making the surface uneven and creating an imbalance in the rotor. Machining, or turning, the rotors will remove these deposits from the rotor surface but it will also remove rotor material itself. This will decrease the ability of the rotor to abosrb and then dissipate heat. It also causes other damage. Unless they're centerless ground, turning them will hurt your braking. I never turn rotors.

Turning on a conventional brake lathe makes a spiral groove in the disc. The grove left forces you to push harder on the pedal for the same amount of braking, and in severe cases can adversely affect ABS engagement. I buy new rotors with a centerless ground factory finish and run them until they're either cracked beyond limits (if drilled or slotted) or worn beyond limits. When the pads wear out, I just put in new pads and bed them in.

So lets blame the pads or lack of bedding, because it likely has very little to do with the rotor itself and is more likely due to a cheap low dusting pad compound. Provided I can find new Stinger specific pads, I will swapping pads ASAP to a known compound that performs much better.

 

[eflyguy]

It is really hard for me to believe that any modern Brembo would "warp." Typically it is pad material "melted" to the rotor making the surface uneven and creating an imbalance in the rotor.

Pretty sure I posted the same comment above.

That's what I came to understand when researching how I could remedy a bad pulsing under braking on my Sorento by myself (new rotors and pads).

The ones I bought came with a specific "break in" procedure, and as much as I love no longer having the pulsing, and having a better "feel" in the pedal, I'm most happy about understanding why the issue occurs. Coming to a complete stop with hot brake components, then holding the vehicle with the brakes, will deposit pad material onto the rotors. This happens because the resins that hold the pad material together does break down under extreme heat.

My opinion, which is just that, is that having "better" brakes (Brembos) is causing the Stingers brakes to run hotter than the average vehicle, and most people are not aware of the issue I described above. I wasn't either - but now that I am, it explains pulsing issues I've had with both cars and motorcycles. I drive my Sorento hard, and brake excessively at times. I have always used the brakes to hold the vehicle stationary - why wouldn't you? Same on one of my motorcycles (but only one - it was the fastest, most nimble, and fun to ride, but hard braking was the norm), I had a pulsing issue when coming to a stop. I rode that bike a lot around town, and I pretty much always hold the bike with the front brake when stationary. Bike rotors are much thinner, and I now realize what was happening.

 

[Helo58]

This is a bedding/pad problem and nothing else. The rotor size and design is typical of a performance/GT car of this size and is likely not the problem unless they were made with improperly heat treated Japanese steel (highly unlikely) or something like that. These rotors can glow cherry red on a track day and will be no worse for the wear if the pads chosen for the car are in the proper heat/material/friction range.

OEMs get pad choices wrong all of the time. This is one of the most notorious and recent:
Z Meets Wall: We Investigate Why the NISMO Z's Brakes Failed at Lightning Lap

Bed in the stock pads. Everyone reading this, bed in your pads. 70-20 mph until they smoke. Keep the car rolling and never drop below 10-15mph. Do this 5-7 times and then drive the car normally for about 15 minutes. If you go through this process prior to any vibration presenting itself or when the car is new, it will be interesting to see who still has vibration problems.

If problems still present in owner's cars after a proper bedding of the brakes, insist on NEW rotors and alternate brake pads (non stock/OEM). It would be safe to say at that point that the stock pads are a poor choice and aftermarket pads (Project Mu, EBC, Jurid, etc.) would be better. New rotors are a must too. Turned rotors may have been great on your wife's Beetle or your old Grand Prix, but it is a bad idea on any car meant to be driven aggressively. Turning creates a groove like on a record that causes the pads to move up and down under braking forcing them to engage and disengage from the braking process.

 

[BrianAx]

For some great info read these articles:
www-brakeandfrontend.com/warped-rotors-myth/
www-hendonpub.com/resources/article_archive/results/details?id=1787#comments

Since I'm new I cant post links, so I had to get creative with how I posted these so please remove the - after the "www" and replace it with a "."

 

[Mach_Tuck]

This is a bedding/pad problem and nothing else. The rotor size and design is typical of a performance/GT car of this size and is likely not the problem unless they were made with improperly heat treated Japanese steel (highly unlikely) or something like that. These rotors can glow cherry red on a track day and will be no worse for the wear if the pads chosen for the car are in the proper heat/material/friction range.

OEMs get pad choices wrong all of the time. This is one of the most notorious and recent:
Z Meets Wall: We Investigate Why the NISMO Z's Brakes Failed at Lightning Lap

Bed in the stock pads. Everyone reading this, bed in your pads. 70-20 mph until they smoke. Keep the car rolling and never drop below 10-15mph. Do this 5-7 times and then drive the car normally for about 15 minutes. If you go through this process prior to any vibration presenting itself or when the car is new, it will be interesting to see who still has vibration problems.

If problems still present in owner's cars after a proper bedding of the brakes, insist on NEW rotors and alternate brake pads (non stock/OEM). It would be safe to say at that point that the stock pads are a poor choice and aftermarket pads (Project Mu, EBC, Jurid, etc.) would be better. New rotors are a must too. Turned rotors may have been great on your wife's Beetle or your old Grand Prix, but it is a bad idea on any car meant to be driven aggressively. Turning creates a groove like on a record that causes the pads to move up and down under braking forcing them to engage and disengage from the braking process.

So, can one bed the brakes even if not new...obviously i purchased the car with more than 0 miles on it. I have approx 2300 right now. No pulsing no vibrations yet. I figured these would be pre-bedded during PDI but that was a bas assumption.

With regard to holding the brakes to keep the car from moving...due to torque converter, is the only option to shift to Neutral? My M3 is SMG (paddle shift) but does not have a torque converter but rather an actual clutch that when stopped does not make the car roll forward. No brake pressure is needed. I am thinking shift to N in the stinger may be the best bet if have to be stopped for a time after brakes heat up...thoughts?

 

[Helo58]

So, can one bed the brakes even if not new...obviously i purchased the car with more than 0 miles on it. I have approx 2300 right now. No pulsing no vibrations yet. I figured these would be pre-bedded during PDI but that was a bas assumption.

With regard to holding the brakes to keep the car from moving...due to torque converter, is the only option to shift to Neutral? My M3 is SMG (paddle shift) but does not have a torque converter but rather an actual clutch that when stopped does not make the car roll forward. No brake pressure is needed. I am thinking shift to N in the stinger may be the best bet if have to be stopped for a time after brakes heat up...thoughts?

The short answer to your question is yes. If you have no pulsation, you bed the brakes now and it will help. Bedding the pads ensures full contact by the pad to the rotor and cures out any resins used to bind the pad materials.

Now everyone should keep in mind, that if the choice of pads by KIA is a bad one, that bedding the pads will not solve the problem. It will continue to happen to users likely resulting in a fix from KIA to replace pads with a new compound. If the compound is wrong for this application, they will continue to melt/transfer material until the pad material is depleted and new pads are required.

With regard to your transmission question, with proper pads and/or bedding, using the brakes during normal driving isn't an issue. The concern with braking is only during the bedding process. It is during this time of bedding where you will perform several (up to 10) aggressive and consecutive braking events from 70 to 20. Do not brake so hard that the ABS is engaged however. The reason for the lower threshold of 20 is to ensure that the car doesn't stop and airflow is still going over the braking system. If the car were to stop completely during this process , it is then that the pad material would transfer to the rotor. Provided you have a relatively traffic free area, this process should take no longer than 10 minutes or so. Cruise for several miles without using the brakes after the stops have been completed.

Once the bedding process is complete, and assuming that the pads are not faulty, there is no reason that you can't use your brakes to stop the car and hold it still as you normally would. There is no need to shift to neutral (N) during complete stops at traffics lights or stop signs, etc. This holds true even if the brakes are hotter than normal.

 

[Mach_Tuck]

The short answer to your question is yes. If you have no pulsation, you bed the brakes now and it will help. Bedding the pads ensures full contact by the pad to the rotor and cures out any resins used to bind the pad materials.

Now everyone should keep in mind, that if the choice of pads by KIA is a bad one, that bedding the pads will not solve the problem. It will continue to happen to users likely resulting in a fix from KIA to replace pads with a new compound. If the compound is wrong for this application, they will continue to melt/transfer material until the pad material is depleted and new pads are required.

With regard to your transmission question, with proper pads and/or bedding, using the brakes during normal driving isn't an issue. The concern with braking is only during the bedding process. It is during this time of bedding where you will perform several (up to 10) aggressive and consecutive braking events from 70 to 20. Do not brake so hard that the ABS is engaged however. The reason for the lower threshold of 20 is to ensure that the car doesn't stop and airflow is still going over the braking system. If the car were to stop completely during this process , it is then that the pad material would transfer to the rotor. Provided you have a relatively traffic free area, this process should take no longer than 10 minutes or so. Cruise for several miles without using the brakes after the stops have been completed.

Once the bedding process is complete, and assuming that the pads are not faulty, there is no reason that you can't use your brakes to stop the car and hold it still as you normally would. There is no need to shift to neutral (N) during complete stops at traffics lights or stop signs, etc. This holds true even if the brakes are hotter than normal.

Thanks! Looks like ill be out bedding some pads this evening...now to find a suitable area!

EDIT: The remainder of your explanation on the transmission and stop and go all makes sense as well!

 

[Joeh1974]

Well. only 1000 miles on the car so far. Decided to bed my brakes today after work. Gave it about 10 accelerations up to 60 and then firm brake down to 15. Coasted around for about 10 minutes after that.

Brakes don't feel nearly as "touchy" as they did before. Rotors were still hot to the touch when I parked the car, but it's about 103 degrees ambient outside right now.

Hope it works out!

 

[robz32]

I have 6300 miles on mine and dont have a single issue with brakes. I think the drivers who have experienced this problem are applying excessive pressure on the brakes when stopped at a light or during traffic jams.

Rotors are made of metal, and with heat metal becomes maleable and can easily be deformed with enough pressure. If you have been driving and using your brakes quite often and the ambient temperatures are high as well, be mindful of how much pressure you are applying on the brakes when the car is completely stopped.

After coming to complete stop. Find the the right amount of braking pressure needed to keep the car from moving by gradually releasing the brake pedal until the car start moving a little, this will help prevent warpped rotors.

 

[Helo58]

I have 6300 miles on mine and dont have a single issue with brakes. I think the drivers who have experienced this problem are applying excessive pressure on the brakes when stopped at a light or during traffic jams.

Rotors are made of metal, and with heat metal becomes maleable and can easily be deformed with enough pressure. If you have been driving and using your brakes quite often and the ambient temperatures are high as well, be mindful of how much pressure you are applying on the brakes when the car is completely stopped.

After coming to complete stop. Find the the right amount of braking pressure needed to keep the car from moving by gradually releasing the brake pedal until the car start moving a little, this will help prevent warpped rotors.

This could not be more INCORRECT! By spreading misinformation on the forum, you are doing the members a disservice. Anyone reading this entire post should ignore it. Please tell me that this was a poor attempt at humor?

For the record, it would take over 1500 degrees Fahrenheit to make steel malleable. Your rotors will never be easily deformed in a "plastic" way. This is an engineering term and I am not referring to polymers. If your rotors ever reached 1500 degrees F, you've got bigger problems than vibration. Someone is pointing a high powered laser at your rotors or the devil has his pitchfork wedged in your calipers. That is the only way your brakes would ever get to 1500 degrees F. Brake pads would break down long before 1500 degrees and would cease to make friction, brake fluid would boil off and the brake pedal would go straight to the floor, again reducing braking friction (and heat). Your car will literally hit a wall or something else long before you ever get to 1500 degrees F. Forget vibration at this point, your brake system would likely be a raging fire at this point. Worst case scenario under rigorous and repeated use, your brakes may see 1000F. No where near enough to make them malleable.

 

[robz32]

Okay first off no one is wanting to spread misinformation about anything. We are just trying to share information and discuss different points of views. Second, that was not an attempt at humor it was an attempt to explain what I had done in my years of driving automatic transmission vehicles and have not suffered from premature warped rotors on any of them until they had reached their service life.

I do understand that the metal of the rotor is harder than the brake pad applying friction to it, the pad wears down while the rotor remains largely unaffected. With excessive heat, the metal becomes soft enough for the pad to wear down the rotor surface. This means that slightly less dense spots in the metal wear down faster and make the harder spots stick out, causing warping.

 

[BlackGhost]

I have to say, I'm heartened by the good info coming in thru this forum in general. Let's keep it coming.

I'm learning a lot on this topic, esp from Helo58 about bedding in etc. I need to find an open road sometime soon it seems.....

Which begs various questions to/from Kia about how to manage your brakes. This will start to plague them, as soon as the sales increase, unless they make some fixes. Does the customer really need to follow a bedding in technique, or do we need a better pad to start with?

 

[Waynerm002]

Keep in mind this car was designed to be a GT car and while it has a powerful engine and great brakes, KIA, as with most manufacturers provide brakes that are more than sufficient for normal use. I think over time we will gain more info to see if this is a manufacturer issue or a consumer use issue. It's good to get information from folks in the know.

 

[Helo58]

Okay first off no one is wanting to spread misinformation about anything. We are just trying to share information and discuss different points of views.

Your attempt to "double-down" on this topic further illustrates that you have no idea of what you are talking about and that forum members should disregard your input on this particular topic. I appreciate your experiences and your willingness to help, but in this case you are not sharing information, you are sharing MIS-information.

Second, that was not an attempt at humor it was an attempt to explain what I had done in my years of driving automatic transmission vehicles and have not suffered from premature warped rotors on any of them until they had reached their service life.

This problem has absolutely nothing to do with automatic transmissions and would have happened with a manual transmission as well.

I do understand that the metal of the rotor is harder than the brake pad applying friction to it, the pad wears down while the rotor remains largely unaffected.

Where you are going wrong is in your understanding about the actual material properties of the components involved. Hardness (engineering term) of the brake rotor is irrelevant in this case. For the intents and purposes here, it is entirely possible and quite easy to design a brake pad with a surface hardness higher than the rotor. In any event, it isn't the primary consideration here.

The brake pad doesn't apply friction to the rotor. The hydraulic piston(s) in the caliper press the pad(s) and rotor together creating friction between the interfacing surfaces. The coefficient of friction (Mu) between the rotor material and the pad material for a given temperature range is the primary concern when speaking of pads and rotors. Both pads and rotors will wear during normal brake use.

With excessive heat, the metal becomes soft enough for the pad to wear down the rotor surface.

For the second time, no. This is incorrect. I don't know why you continue to put this out here for members to read.

No amount of "excessive heat" generated by a functioning or even malfunctioning braking system will ever amount to enough to make the metal soft or malleable. It simply isn't possible, excepting the ONE in ONE MILLION chance of something truly odd happening. The brakes will simply stop working rather than continue to generate heat to the point where the rotors would become malleable. As stated before, the pads would disintegrate, and the brake fluid would boil off eliminating your ability to hydraulically actuate the caliper piston.

This means that slightly less dense spots in the metal wear down faster and make the harder spots stick out, causing warping.

There are no hard or less dense spots on our brake rotors. Manufacturing processes simply don't allow variations in density throughout a homogeneous material such as the steel used in brake rotors. My guess is that Brembo takes additional steps to ensure that their metallurgy is beyond reproach. Actual rotors from the production line at Brembo would likely be randomly pulled from the line during production and the material properties tested to determine if they meet spec. There are no "harder spots" sticking out. It is simply brake pad material that has melted and stuck to the rotor surface.

With the Stinger, we aren't talking about one in a million occurrences. Several people have noticed the vibration. This isn't a rotor problem. It is a pad problem, plain and simple

 

[Helo58]

I have to say, I'm heartened by the good info coming in thru this forum in general. Let's keep it coming.

I'm learning a lot on this topic, esp from Helo58 about bedding in etc. I need to find an open road sometime soon it seems.....

Which begs various questions to/from Kia about how to manage your brakes. This will start to plague them, as soon as the sales increase, unless they make some fixes. Does the customer really need to follow a bedding in technique, or do we need a better pad to start with?

As braking systems increase in capability, the components within them become more specialized and expensive. To achieve higher performance levels, different materials are used to make Stinger components vs. Rio components (for example).

Simply put, you can drive your regular car, truck, or minivan for years and never bed your pads. However, with higher performance car's brakes the pad compounds are different and require different treatment. As such they require bedding for maximum performance to be realized.

It remains to be seen if these problems are occurring because of an improperly bedded pad or because of an inferior pad compound... or both heaven forbid.