Brake Rotors Warped?

[Greg]

My 09 1/2 G8 GT feels like it has warped brake rotors - will about 500 miles on it! Any stop from a speed greater than 40 MPH gives me the pulsing feel. The dealer says it's normal and they want to turn the rotors. Does this seem right?

[BigRob]

its not normal, i doubt they did the brandishing procedure. go to another dealer. mine did this at 2k, they did it, went away for a bit, then came back. they ended up turning them for free.

oh shit, i misread your post. i thought you said they didnt want to turn them for you. just have them turn them you will be fine

[Blackdevil77]

I have the same pulsing. What is the brandishing procedure???

[99-LS1-SS]

Unless you are in a panic stop and the ABS is kicking in you should not feel pulsing when you slow down.

[BigRob]

I believe it to be a procedure of rapid acceleration and braking to help break In the pads or something like that.

[BigRob]

Also, I believe it must be done when pretty new, or at very low miles. If at higher miles this occurs, I believe that they will attribute the pulsing to a warped rotor from wear and tear. I got mine turned after 2k for free after they did the brandishing procedure twice, and it didn't work.

[r33pwrd]

mine did this when new... (from about 500 miles as well) but it actually went away after a few hundred miles and has not come back @ 6K miles.

[Chewy]

It usually comes from torquing the lugs at different rates. I'm sure you haven't had the wheels off since it only has 500 on it but I have found most cases come from shops using torque sticks or just an impact until tight.

[syP]

undo lugnuts..

retorque them.


I had the same problem.. no visible problems... fixed it after re-torquing.

[daviddrift]

ive read this article from StopTech that theres no such thing as warped brake rotors.


the cause of brake vibrations or shimmies is the result of uneven transfer of brake pad material to the rotor, thus causing the variations in the rotor surface.

Standard road cars use brakes that function mostly by abrasion, or the breaking down of the bonds between the pad material molecules by the friction generated by pushing the pads against the rotors. Under normal city conditions, the worn-away pad material is simply carried away as brake dust (the black dust commonly seen on wheels). However, under heavier braking, such as an emergency stop or slowing down from a highway exit, the brakes become much hotter, and that material can actually 'cook' to the brake rotors (http://www.autopartswarehouse.com/brakes_-and-_rotors~pop.html).

The best way to aid in this 'cooking' process is to keep the pads in constant pressurized contact with the rotors... by remaining firmly on the brakes after the vehicle has come to a complete stop.

As the pad material bonds to the rotor, the surface of the rotor then becomes uneven, and the brakes begin to vibrate at high speeds. The brake rotors do not warp, however. Even the most extreme braking conditions on public roads do not generate enough heat to cause the brake rotors to warp.

FYI guys:cheers:

[Devilish34]

I had his on my G8 until I put the DBA rotors on. Now it stops like it should smooth.

[GeorgeInNePa]

I have the same pulsing. What is the brandishing procedure???

That's when I get drunk, the bartender cuts me off and I start waving a gun around.

[todds87ss]

ive read this article from StopTech that theres no such thing as warped brake rotors.



FYI guys:cheers:

I've heard this before...complete garbage. Anyone who has turned rotors can tell you that there is indeed some warpage that happens on occasion. Those that think there is no such thing should hang out at your local machine shop for a day...

[BlackGT5]

The proper term is burnishing (not brandishing).

And what is shown in the Stoptech article is not garbage but in fact very true. The "transfer layer" left by the brake pad needs to be even across the rotor swept area or high & low spots will develop.

Take for example this picture of a rotor with a poor transfer layer. You can see the area in the center does not have the dark (friction material) layer as seen in other parts of the rotor. Over time, the rotor will develop a low spot there. These high and low spots result in pedal pulsation felt by the driver.

http://i582.photobucket.com/albums/ss266/blackgt5/Poortransferlayer.jpg

The picture below is of a rotor with good transfer layer. This rotor will be less likely to develop high/low spots and thus less prone to pulsation felt by the driver.

http://i582.photobucket.com/albums/ss266/blackgt5/Goodtransferlayer.jpg

This is not to say that a poorly made rotor can cause pedal pulsation on it's own but when customers complain about pulstion on a new car, the OEM will ask the pad supplier for their input first.

[bwooten492]

Unless you are in a panic stop and the ABS is kicking in you should not feel pulsing when you slow down.

Dude you have Brembo's!

to the OP mine does the same thing...

[-Ray-]

I've heard this before...complete garbage. Anyone who has turned rotors can tell you that there is indeed some warpage that happens on occasion. Those that think there is no such thing should hang out at your local machine shop for a day...

I having deja vu all over again.

It's called radial runout now. but yes, it does happen. in fact, there's a manufacturers spec limit for it.

[Monty]

I had his on my G8 until I put the DBA rotors on. Now it stops like it should smooth.

+1

[SRG963]

Greetings, What's the best CAI?

















j/k lol

[rez0nance]

greetings, what's the best cai?

















J/k lol

lmao.

[-Ray-]

Greetings, What's the best CAI?



Is there a point to this?

[99-LS1-SS]

that's when i get drunk, the bartender cuts me off and i start waving a gun around.

lmao!

[todds87ss]

I having deja vu all over again.

It's called radial runout now. but yes, it does happen. in fact, there's a manufacturers spec limit for it.

Sorry, couldn't help myself.