[travislambert]

If you measure, be sure to sand the rotors first to remove the pad deposits. That way you're only measuring the rotor itself.

[Junkyardspecial]

Rotors dont warp, its pad deposits. I can't believe people still perpetuate that myth.

[len_eng]

The dealer actually measured the rotors and found the runout to be out .008 on one side and .005 on the other side

[cdb95z28]

A good read:
https://centricparts.com/getmedia/bd...c-8-2018_1.pdf

I agree with Travis and the uneven transfer crowd here. 99 times out of 100 it’s going to be uneven transfer. And to appease Murphy’s Law, The other 1 out of 100 is going to be someone who extremely abused their brakes then drove thru flood waters, lol.

Buy this and clean off the uneven deposits:



https://www.amazon.com/dp/B007INTEMC...v_ov_lig_dp_it

There is a rare chance that if the car was driven a lot of miles with the uneven deposits, and the brakes were used hard to the point where the vibrations got extremely worse, that could negatively change the metallurgical properties of the iron. This change will perpetuate the uneven transfer layer. But if caught early, the rotors can be renewed to a fresh surface.

Travis mentioned washing the car and not getting the brakes dry, I agree with this also. And I also found that some wheel cleaners can remove transfer layer and cause pedal vibrations. I used to use Meguiar’s purple spray bottle wheel cleaner. I now use their wheel cleaner in the blue bottle.

The rotors on the SS 1LE and ZL1s are Brembo. I can’t say if a regular SS has Brembo rotors though.

[Future1LEa10]

Originally Posted by len_eng

The dealer actually measured the rotors and found the runout to be out .008 on one side and .005 on the other side

But didn't you hear, warping of rotors is a myth....LOL Heat does nothing to metal. Nothing I tell you...

[Junkyardspecial]

Originally Posted by Future1LEa10

But didn't you hear, warping of rotors is a myth....LOL Heat does nothing to metal. Nothing I tell you...

Runout and warping are two very very different things.

[Future1LEa10]

Originally Posted by Junkyardspecial

Runout and warping are two very very different things.

Is that right... So runout occurs from what then? "pad deposits"?? Lol This has ran its course gents. I'm out.

[Junkyardspecial]

Originally Posted by Future1LEa10

Is that right... So runout occurs from what then? "pad deposits"?? Lol This has ran its course gents. I'm out.

A quick google will teach you everything you need to know. You really should stick around, you could learn something, cognitive dissonance is such a shame really.

[EJR8402]

Originally Posted by cdb95z28

A good read:
https://centricparts.com/getmedia/bd...c-8-2018_1.pdf

I agree with Travis and the uneven transfer crowd here. 99 times out of 100 it’s going to be uneven transfer. And to appease Murphy’s Law, The other 1 out of 100 is going to be someone who extremely abused their brakes then drove thru flood waters, lol.

Buy this and clean off the uneven deposits:

Attachment 1068062

https://www.amazon.com/dp/B007INTEMC...v_ov_lig_dp_it

There is a rare chance that if the car was driven a lot of miles with the uneven deposits, and the brakes were used hard to the point where the vibrations got extremely worse, that could negatively change the metallurgical properties of the iron. This change will perpetuate the uneven transfer layer. But if caught early, the rotors can be renewed to a fresh surface.

Travis mentioned washing the car and not getting the brakes dry, I agree with this also. And I also found that some wheel cleaners can remove transfer layer and cause pedal vibrations. I used to use Meguiar’s purple spray bottle wheel cleaner. I now use their wheel cleaner in the blue bottle.

The rotors on the SS 1LE and ZL1s are Brembo. I can’t say if a regular SS has Brembo rotors though.

Thank you, I'll try this out.

I don't actually use a dedicated wheel cleaner. Car shampoo, wheel brush, and horsehair detailing brush for the delicate areas only.

[EJR8402]

Originally Posted by travislambert

Another common cause is washing a car without driving afterwards to dry the brakes. The metal in the pads will corrode and stick to the rotors, all in one spot of course.

I have certainly done this on more than one occasion. No more.

[Rayvan]

Originally Posted by Future1LEa10

But didn't you hear, warping of rotors is a myth....LOL Heat does nothing to metal. Nothing I tell you...

Dude. An eyebrow hair is .005"

That's not a warp.

[EJR8402]

Seems like all the articles online that I've read about the "misconception of brake rotor warping" hone in on the premise that you don't have "warping", just uneven wear. Excess runout typically occurs from the pads wearing the rotors unevenly, probably due to an imbalance in the rotor. It's not "warping" like you'd see with a piece of wood, but the essence of it is the same: it's a physical imperfection in the rotor surface, causing the pad to make inconsistent contact with the rotor. Whether you call it a warp or uneven wear, the available solutions are the same: re-surface the rotor, or replace it.

For the record, I don't see anything like "uneven pad deposit" on my rotors. I've researched and seen photos of this and that's not what's going on here. I imagine the solution for that would be to lightly scuff the rotors with some high grit sandpaper or to use something like the drill attachment linked earlier.

Any time the wheels are removed and re-mounted, there's a chance that they'll be remounted unevenly and cause uneven wear. My take-aways here are to tighten down lugs in a star pattern always (or re-do the job correctly after you hand the car to someone else to rotate/balance, etc.), and make sure to get brakes dry after a wash and drive it afterward for a few minutes.

[cdb95z28]

Don't overlook any corrosion on the wheel, rotor hat and wheel bearing faces. Any corrosion here can cause runout.

[EJR8402]

Originally Posted by cdb95z28

Don't overlook any corrosion on the wheel, rotor hat and wheel bearing faces. Any corrosion here can cause runout.

One more reason to do a wheels-off detail every now and then.