FAQ: Vibration under braking: warped rotors? NO!

[davebo]

Well thanks for all the replies. It didn't bother me much during "drive my kid to preschool" season which is beginning again shortly, but if it does irritate me I may look into those Z17 pads Kazz, thanks.

 

[Volfy]

I can't think of any place anywhere near me where I could safely get up to 80mph, brake to 5, then repeat 4 more times, and then sit in my car for 2 hours while they cool off.

Brake pads that require that sort of temp are typically track compounds, which doesn't sound anything like what you are after. Bedding procedures vary. Most street-oriented compounds don't require that level of heating up the pads.

Besides, there is absolutely no need to "sit in my car for 2 hours". I'm guessing you're referring to instructions that says to let the brakes cool for 2hrs. It doesn't mean you cannot drive or touch the brakes. In fact, the best way to cool the brakes is to drive it gently. That produces air flow over the brakes that cools it far better than letting the car sit static.

 

[davebo]

Brake pads that require that sort of temp are typically track compounds, which doesn't sound anything like what you are after. Bedding procedures vary. Most street-oriented compounds don't require that level of heating up the pads.

Oh I didn't mean on new pads, I just meant the OP's instructions about clearing the already present pad material off the current rotors.

 

[BC00]

Continuing the story.

The dial indicator tool showed that my almost new EBC slotted rotor in the driver side is warped. Did the resurface, but this time in another shop and keeping the rotor on the hub.

I still can't understand how the rotors gets warped not driving in the track...

 

[Snicklefritz]

Continuing the story.

The dial indicator tool showed that my almost new EBC slotted rotor in the driver side is warped. Did the resurface, but this time in another shop and keeping the rotor on the hub.

I still can't understand how the rotors gets warped not driving in the track...

Rotors don't "warp" except from extreme heat. That's just science. It's physically impossible to warp without heat, a lot of it. Your "warp" is likely pad deposits, and a lot less likely a manufacturing flub.

 

[D.J.]

Rotors don't "warp" except from extreme heat. That's just science. It's physically impossible to warp without heat, a lot of it. Your "warp" is likely pad deposits, and a lot less likely a manufacturing flub.

Could easily be an unclean hub/rotor interface.

A few flakes of rust would easily cause an indicated runout .

On-car brake lathe is the way to go to ensure zero runout.

 

[cLaw]

Hey all, trying to read through the 58 pages and there are a lot of different answers, just gonna keep this short and simple.

Bought car at 30k miles, they gave me the car with brand new pads on them. Didn't feel any pulsing for a while until around 38k miles? I'm now at 45k and I purchased EBC red pads this week.

My question is, should I buy new rotors as well since its been 45k miles worth of deposits basically? I'm sure the pads were replaced on my purchase due to the car pulsing before hand. Should I try to resurface or turn the rotor? (When I say "I", I mean tell the shop). Or is it easier to just go brand new rotors and brand new brake pads for peace of mind?

 

[djerickd]

I would resurface it anyways

 

[Volfy]

Hey all, trying to read through the 58 pages and there are a lot of different answers, just gonna keep this short and simple.

Bought car at 30k miles, they gave me the car with brand new pads on them. Didn't feel any pulsing for a while until around 38k miles? I'm now at 45k and I purchased EBC red pads this week.

My question is, should I buy new rotors as well since its been 45k miles worth of deposits basically? I'm sure the pads were replaced on my purchase due to the car pulsing before hand. Should I try to resurface or turn the rotor? (When I say "I", I mean tell the shop). Or is it easier to just go brand new rotors and brand new brake pads for peace of mind?

$19.99 will tell you right quick if you might need new rotors. 6 in. Digital Caliper with SAE and Metric Fractional Readings

Rotor service thickness limit here: https://www.kstinger.com/disc_brakes_and_pads-351.html

There are a few other considerations, but above is a main one. Unless your rotors are anywhere near the service limit, resurfacing works just fine and even have some advantages over brand new ones.

 

[D.J.]

$19.99 will tell you right quick if you might need new rotors. 6 in. Digital Caliper with SAE and Metric Fractional Readings

Rotor service thickness limit here: https://www.kstinger.com/disc_brakes_and_pads-351.html

There are a few other considerations, but above is a main one. Unless your rotors are anywhere near the service limit, resurfacing works just fine and even have some advantages over brand new ones.

Resurfacing, specifically on car, has the added advantage of virtually guaranteeing zero run out.

Mine were:
Measured 29.85mm before
Measured 29.25mm after

Speak is nominal = 30.0mm
Service limit = 28.4mm
N

https://imgur.com/a/4e0H2cl

 

[JPark]

Could easily be an unclean hub/rotor interface.

A few flakes of rust would easily cause an indicated runout .

On-car brake lathe is the way to go to ensure zero runout.

I have read so many issues on the warped rotors question on many Kia vehicles but not clear on the real problem but that i think there is a Kia fault here in the production of there vehicles.
I have a 2023 Sportage only a year old and 20,000 miles on it. I drive almost a 100 miles a day to and from work and if any errands after work. I had the dealership tell me that i warped my rotors by breaking hard. First i drive mostly on the surface streets rarely on the freeway unless i have to, and second if you ever have driven in Phoenix, AZ. you know people are stupid crazy and do not know how to drive here so you may have to tap the breaks here and there because the idiot cut in front of you or they waited to stop and turn at the last possible second because they do not know what they are doing. So why are they charging me for warped rotors to be turned when any other vehicle i have ever owned never have i had to turn a rotor. And now have it done twice in the last two months on a new vehicle? I do not do down hilling on any regular basis or do i speed then try to stop on a dime. I just do normal driving with the occasional avoid a hazard like pot hole or dumb driver, but never lock up my brakes or ride them for a long period. If they tell me this again when i take in for service tomorrow i will just spend the money and buy better product from somewhere else. I am also taking it in as the said i need an alignment and a throttle body replaced. Hmm, questionable again on such a new vehicle and all my other vehicles i did regular out of state trips and not one trip on this vehicle and has been in the shop twice as many times as the others. Thank you for any light shed on this situation.

 

[D.J.]

If they tell me this again when i take in for service tomorrow i will just spend the money and buy better product from somewhere else.

You mean, like a different make/model of vehicle?

Or a different brand of brake pad and/or rotor?
I was unaware that Kia Sportages suffered from brake pulsations. I wonder if it is pad deposits like the Stinger, or if yours are actually out of round.

 

[Snicklefritz]

Here is my guess. Kia North America spec brake pads are all the same. A few vehicles in each model will suffer pulsating brakes. Try bedding the pads, and if the pulsating diminishes do it again, and if the pulsating goes away, get new aftermarket brake pads on right away before the pulsating returns. Your rotors are fine in this case. If you cannot bed the OEM pads successfully, your rotors are badly caked with pad deposits and need to be turned. Sounds like "your" dealership wants to do this and charge you, which tells me that they are in it for the money more than customer satisfaction - and that is typically shortsighted of them. Get the rotors turned and go aftermarket pads. Don't bed them in, go easy for the first few hundred miles, maybe 600 like the manual advises for break in period on a new vehicle. Braking easy will wear the whole surface of the pad evenly to the rotor and it should be smooth braking after that, even emergency braking, and no pad deposits. If you find the problem returns, read further up in this thread for suggestions. It is super rare for aftermarket pads to cause the pulsating problem on a Stinger. And I can't think that it would be different on a daily driver Sportage.

I have read so many issues on the warped rotors question on many Kia vehicles but not clear on the real problem but that i think there is a Kia fault here in the production of there vehicles.
I have a 2023 Sportage only a year old and 20,000 miles on it. I drive almost a 100 miles a day to and from work and if any errands after work. I had the dealership tell me that i warped my rotors by breaking hard. First i drive mostly on the surface streets rarely on the freeway unless i have to, and second if you ever have driven in Phoenix, AZ. you know people are stupid crazy and do not know how to drive here so you may have to tap the breaks here and there because the idiot cut in front of you or they waited to stop and turn at the last possible second because they do not know what they are doing. So why are they charging me for warped rotors to be turned when any other vehicle i have ever owned never have i had to turn a rotor. And now have it done twice in the last two months on a new vehicle? I do not do down hilling on any regular basis or do i speed then try to stop on a dime. I just do normal driving with the occasional avoid a hazard like pot hole or dumb driver, but never lock up my brakes or ride them for a long period. If they tell me this again when i take in for service tomorrow i will just spend the money and buy better product from somewhere else. I am also taking it in as the said i need an alignment and a throttle body replaced. Hmm, questionable again on such a new vehicle and all my other vehicles i did regular out of state trips and not one trip on this vehicle and has been in the shop twice as many times as the others. Thank you for any light shed on this situation.

 

[baws22489]

My dealer did the same thing and now I am working with Customer support to try to get my rotors replaced. I told you all a year ago the service manager charged me $400 to resurface the rotors at 12k. I replaced the pads 1K miles later but the wobble returned. Took in again at 23k miles and now he says the front rotors are below specs and need to be replaced at $800. I go how did they become out of spec when you were the last person to work on them. I opened a case with customer support and of course the service manager wont respond the the case rep to provide me "goodwill" and do the replacement of the rotors for free.

So I am going to another Kia dealer and see if they can do something about these rotors with 25k miles on them. If not I will buy after market rotors/pads and be done with it.

Should I be concerned for my safety with the rotors runout quoted to be 28mm as they shake bad when they get hot from driving for longer than 30 miles and stopping a lot?

 

[Ron]

Hey all, trying to read through the 58 pages and there are a lot of different answers, just gonna keep this short and simple.

Bought car at 30k miles, they gave me the car with brand new pads on them. Didn't feel any pulsing for a while until around 38k miles? I'm now at 45k and I purchased EBC red pads this week.

My question is, should I buy new rotors as well since its been 45k miles worth of deposits basically? I'm sure the pads were replaced on my purchase due to the car pulsing before hand. Should I try to resurface or turn the rotor? (When I say "I", I mean tell the shop). Or is it easier to just go brand new rotors and brand new brake pads for peace of mind?

Buy new rotors and make sure the brakes are new.
You can't put a price on piece of mind.

 

[Thomby]

Brake rotors are very hard, and very long-wearing. I can't imagine taking any serious amount of material off of them in 10-11k miles, but I guess it's possible they were very aggressive when they turned them. You should be able to take reasonable measurements with a cheap pair of calipers (I'd do a handful of points around the diameter) and compare to the spec @D.J. posted above.

For you and anyone else replacing the pads, I'd say take it out and do a series of aggressive stops with the old pads to see if that cleans up your rotors (say from 60-80 down to 10-20 repeatedly) before you go to the expense of replacing the rotors.

 

[Ron]

Rotors are the least expensive part, its the brake pads that are expensive.
My suggestion is do what i did and go to a private shop and replace all the rotors and put in new high quality brake pads and be finished with this never ending thread!.

 

[D.J.]

Rotors are the least expensive part, its the brake pads that are expensive.
My suggestion is do what i did and go to a private shop and replace all the rotors and put in new high quality brake pads and be finished with this never ending thread!.

???

Are you comparing the lowest quality rotors to the highest quality pads?

 

[Ron]

No...That would be foolish.
Especially when we are talking about one of the most important parts of any vehicle.

 

[D.J.]

No...That would be foolish.
Especially when we are talking about one of the most important parts of any vehicle.

Pads (sold in pairs), on average, are cheaper than rotors (sold individually).