FAQ: Vibration under braking: warped rotors? NO!

[D.J.]

I just installed the power stop Z26 front and back. I have a 2018 (was completely stock and original) I bought with extremely low mileage about 18 months ago and soon after got the brake shuddering issue. I followed the advice in this forum and did the "process" but after a few weeks the shudder always came back.
SO I did several hard stops from 60>5mph one more time to clean the rotors off and then swapped stock pads for the Z26 and followed Powerstop's bedding process. I'm still on stock untouched rotors.

Anyway, the Powerstop's have been awesome. What an improvement, feels great! Only thing is, after a couple weeks I'm starting to notice a very very small shudder- nothing like before, extremely minor, barely noticeable. But I notice it.

Any thoughts on best way to eliminate?

Machine the rotors.. that will fix it.
I did, on car lathe for best results...

On car lathe - 2018 Kia stinger

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

 

[seeyainakia]

Machine the rotors.. that will fix it.
I did, on car lathe for best results...

On car lathe - 2018 Kia stinger

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

That sounds awesome. And expensive. And probably no where near me. Was thinking if I should get them turned before the new pads and I probably should have, but damn I've been lazy lately

 

[Volfy]

I just installed the power stop Z26 front and back. I have a 2018 (was completely stock and original) I bought with extremely low mileage about 18 months ago and soon after got the brake shuddering issue. I followed the advice in this forum and did the "process" but after a few weeks the shudder always came back.
SO I did several hard stops from 60>5mph one more time to clean the rotors off and then swapped stock pads for the Z26 and followed Powerstop's bedding process. I'm still on stock untouched rotors.

Anyway, the Powerstop's have been awesome. What an improvement, feels great! Only thing is, after a couple weeks I'm starting to notice a very very small shudder- nothing like before, extremely minor, barely noticeable. But I notice it.

Any thoughts on best way to eliminate?

How long after you installed the new brake pads did you do the bedding procedure?

 

[baws22489]

That sounds awesome. And expensive. And probably no where near me. Was thinking if I should get them turned before the new pads and I probably should have, but damn I've been lazy lately

I had mine turned and kept the same stock pads as service manager said that would fix the problem, but the vibration returned after 1,000 miles. So i bought some pads from the k8 store on here and now 4 months later I have the vibration getting worse.

Now I don't know what to do, replace the rotors and pads again at the same time and start new or just the rotors as the pads only have roughly 5k miles on them?

 

[StingertimeNC]

the rotors need to be turned to fix them once and for all. Then put on new pads, and do the bedding process with the new pads and you'll be good. stay away from stock pads though. I've used Hawk HPS 5.0 pads with great success.

I also suspect you could turn the rotors and keep the new pads you have as long as they are not stock.

 

[G-841775]

How long after you installed the new brake pads did you do the bedding procedure?

Immediately. Same day. Was religious about it

 

[D.J.]

I also suspect you could turn the rotors and keep the new pads you have as long as they are not stock.

I fully concur. that is what I would do.

 

[I Stung U]

I had mine turned and kept the same stock pads as service manager said that would fix the problem, but the vibration returned after 1,000 miles. So i bought some pads from the k8 store on here and now 4 months later I have the vibration getting worse.

Now I don't know what to do, replace the rotors and pads again at the same time and start new or just the rotors as the pads only have roughly 5k miles on them?

Just change the pads if rotors were recently turned... it's the stock pads that are bad.. rotors should still be good to go. their strong durable rotors. I changed my rear pads and didn't turn the rotors (which I wanted too, but couldn't find any mechanic shop fkrs to do it), and just said fck it and changed rotors, as they'll conform to the rotors (but my rotors did not have any pulsating at all, so not warped).. so far so good. but the front, 100% I'll get turned before putting on my new Powerstop Z26 pads I have ready and waiting. Found two shops that will turn them.

 

[Volfy]

Immediately. Same day. Was religious about it

That's what kinda worries me. What a lot of folks don't realize - and not all brake pad/rotor mfrs do a good job at explaining properly - is that there are two stages of new brake pad/rotor break-in procedure:

1. Seating. This allows the brake pads and rotors to achieve an even pressure contact. You do this by driving the car - and braking - very gently, with as little brake pedal pressure as possible, to allow the pads/rotors to wear into each other. After each drive, I look at the rotor to see if the entire wearing surface show sign of contact with the brake pad. If not, I'll continue the seating process. If you are starting with brake new pads and brand new rotors, this step likely goes pretty quick, since both are supposedly perfectly "square" and smooth. This is also the reason resurfacing the old rotor (if you wish to keep them) is a good idea with new brake pads. Now, sometimes, if the old rotors are in excellent shape and are quite smooth, you might get away with not turning them. However, it is a risk you take, since the rotor wearing surface may not have a perfectly square contact with the new pads. It is no uncommon for the rotor/pad to wear into a slight bevel, as well as developing some grooving. In any case, it is paramount that you examine the rotor wear to make sure the pads are making even contact BEFORE moving on to the next step.

2. Bedding. This should ONLY be done with the new pads have an even pressure contact with the rotor. The purpose is generally to heat the pad surface evenly above a certain temp to "set" the pad compound, and for the right kind of micro material transfer to take place.

Problem with not seating the new pads properly, especially with old rotors not resurfaced, is that the pads may not make an even contact with the rotor, so there might be high spot that may over-heat and glaze over, before proper bedding can take place. This might wear itself out over time... or it might not and might gets worse.

If you catch it early enough and the pads are not too worn, you might be able to resurface the rotors and re-attempt the seating/bedding steps. The longer/harder you've driven the car, the more you will have worn the brand new pads into the shape of the old rotors, to a point where the new pads are no longer "square" any more against a re-surfaced rotor. Then even with freshly turning rotors, you are starting off again with uneven pressure contact, which you might have to take a longer time to "seat-in" before attempting to the bedding procedure again.

If you've driven on the brakes for a good while, success is still possible but becomes less guaranteed.

 

[BC00]

My story.

Put new pads on OEM rotors. Was ok for a while. I was able to feel waviness on rotors, so doesn't spend time on them.

Brand new EBC rotors and Stoptech pads were put, which were fine for ~3000 miles. The pulsation on pedal started to appear.

All four rotors were resurfaced. For a week was driving very gently in city traffic. Lately made a harder braking and the same pulsation is felt plus steering wheel developed a shakiness. Adding a screen how front and rear rotors look like.

Please advice what should I do further? My guess that seating process isn't finished properly? Maybe I should try new set of pads?

P.S. for some reason the doesn't let to upload photos....

 

[Snicklefritz]

P.S. for some reason the doesn't let to upload photos....

you have to post more to get past 'newish member' status, then you can upload pictures to your posts.

My guess that seating process isn't finished properly?

the stinger owner's manual advises to go easy on the brakes on a brand new car while the engine is breaking in, for 600 miles. I did that and never did bed the brake pads. the oem pads have worked fine for me. but I've also never pounded on the brakes except a handful of emergency stops. your one of the few reporting here that aftermarket pads / rotors have not solved the brake judder issue. start over? and let the seating process take longer as volfy described to square up the whole pad surface to the rotor.

 

[Volfy]

My story.

Put new pads on OEM rotors. Was ok for a while. I was able to feel waviness on rotors, so doesn't spend time on them.

Brand new EBC rotors and Stoptech pads were put, which were fine for ~3000 miles. The pulsation on pedal started to appear.

All four rotors were resurfaced. For a week was driving very gently in city traffic. Lately made a harder braking and the same pulsation is felt plus steering wheel developed a shakiness. Adding a screen how front and rear rotors look like.

Please advice what should I do further? My guess that seating process isn't finished properly? Maybe I should try new set of pads?

P.S. for some reason the doesn't let to upload photos....

No personal experience with Stoptech, so dunno what to expect. EBC makes good rotors, so I can't see that as the problem, especially since you say they and the Stoptech pads were brand new. This is a head scratcher.

Did you dowse the rotors and pads with plenty of brake cleaner before after install? Brand new rotors usually come marinated in preservation oil to prevent rust on the cast iron. I usually spray each rotor with almost a full can of brake cleaner BEFORE installing on car. After everything buttoned up, I spray the assembly just to make sure any finger- or hand-prints were cleaned off. Any oil or grease left on the wearing surfaces will cause the pads compound to glaze over and contact between the pad/rotor to skip.

 

[BC00]

you have to post more to get past 'newish member' status, then you can upload pictures to your posts.

the stinger owner's manual advises to go easy on the brakes on a brand new car while the engine is breaking in, for 600 miles. I did that and never did bed the brake pads. the oem pads have worked fine for me. but I've also never pounded on the brakes except a handful of emergency stops. your one of the few reporting here that aftermarket pads / rotors have not solved the brake judder issue. start over? and let the seating process take longer as volfy described to square up the whole pad surface to the rotor.

Probably will swap the existent pads with new ones, but this time cheap brand. Will see how the brakes will react and how long it will take the judder to appear again.

 

[BC00]

No personal experience with Stoptech, so dunno what to expect. EBC makes good rotors, so I can't see that as the problem, especially since you say they and the Stoptech pads were brand new. This is a head scratcher.

Did you dowse the rotors and pads with plenty of brake cleaner before after install? Brand new rotors usually come marinated in preservation oil to prevent rust on the cast iron. I usually spray each rotor with almost a full can of brake cleaner BEFORE installing on car. After everything buttoned up, I spray the assembly just to make sure any finger- or hand-prints were cleaned off. Any oil or grease left on the wearing surfaces will cause the pads compound to glaze over and contact between the pad/rotor to skip.

I doubt that dealership used any cleaners. Anyway even w/o it, I can't imagine how brand new rotors and pads develop a judder in such a short time. I am not a racer and don't do silly things like washing car after a sprint.

If the judder won't go away with resurfaced rotors and new cheap pads combo, I will start consider something more serious, like floating rotors. This illness of Stinger drives me crazy

 

[SRV]

Brand new EBC rotors and Stoptech pads were put, which were fine for ~3000 miles. The pulsation on pedal started to appear.

All four rotors were resurfaced. For a week was driving very gently in city traffic. Lately made a harder braking and the same pulsation is felt plus steering wheel developed a shakiness.

Did you bed the pads to the rotors per the manufacturer's directions?

 

[davebo]

I was glad to find this thread because I've been having this issue for a while and just assumed it was warping, so I eagerly read the OP. 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. I think I'll just deal with lumpy braking for the time being. I haven't seen any recall on this so I assume replacing everything isn't just covered under warranty, but lumpiness aside I haven't felt like the braking performance is actually hindered any. Am I correct in that, or is there a danger?

 

[D.J.]

I haven't seen any recall on this so I assume replacing everything isn't just covered under warranty, but lumpiness aside I haven't felt like the braking performance is actually hindered any. Am I correct in that, or is there a danger?

No recall, no updated parts
Had my rotors replaced 4 times under warranty. (Canadian warranty was 60k for brakes)

On the last rotor replacement, I replaced the pads and life's been good since.

 

[BC00]

Did you bed the pads to the rotors per the manufacturer's directions?

What kind of directions do you mean?

 

[Kazz]

I was glad to find this thread because I've been having this issue for a while and just assumed it was warping, so I eagerly read the OP. 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. I think I'll just deal with lumpy braking for the time being. I haven't seen any recall on this so I assume replacing everything isn't just covered under warranty, but lumpiness aside I haven't felt like the braking performance is actually hindered any. Am I correct in that, or is there a danger?

I have almost 80,000 miles on my 2018. I've always been good about pad and rotor wear through good braking technique. I've been managing the non-warped rotors (OEM pad build-up) myself. When it vibrates I can brake hard and straight for a long space (interstate exit ramp, for instance) and let off to very light braking by the time I come to a complete stop. The vibrations would be gone - for a while. A few more uses of the brakes and the build-up would return and create the pedal vibration again.

I now have a college student that's a number of hours away and requires a lot of hilly 2-lane driving so I decided it was finally time. I went to Rock Auto so I wouldn't have to worry about fit. I ordered Powerstop "Z17 Evolution Clean Clean Ride with Ceramic" pads (front pads & rear pads) for all of $117. I had the rotors scuffed (I wanted them turned but after a conversation with the service manager they decided to just clean & scuff them up) and the pads installed just last week.

The reason I post this is because their bed-in procedure only requires multiple aggressive stops coming down from 30mph to 5. I was only able to do about a dozen of the 20 repetitions they recommended. I've also taken the opportunity with ramps and other places to aggressively come down from higher speeds a few times. Not sure it helps entirely but I do want to make sure I get rid of as much of that OEM pad crap as possible. I've been very happy so far. Vibrations are gone and the pedal feel is more direct. Happy to report back here if I find problems.

Good luck whatever you choose!

 

[Snicklefritz]

lumpiness aside I haven't felt like the braking performance is actually hindered any. Am I correct in that, or is there a danger?

'lumpiness' isn't a safety issue. nobody likes brakes that get their attention either feel or noise, that's all.