NitrousMan

I have a shimmy in the front end under high speed braking so I'm having the rotors turned and need to install new pads. The rears look almost new so I was going to leave them alone and I believe they are OEM pads. Will I have an issue if I go to ceramic pads on the front and leave the rears alone for now? These are Z06 brakes so I have the six pads on each front caliper. Thanks.

timd38

I would use the same all the way around. I would put OE pads back on the front so the match the rears.

I am sure that lots of people have have mixed them with no problem, but I would not.

Adam@Amp'dAutosport.com

Do not turn your rotors! How many miles on pads and rotors? Do not put ceramics on the front with oem in the rear. The rear will over brake the front.

BEZ06

I don't know why you'd need to turn the rotors!?!?

The Delphi ABS calls it DRP (Dynamic Rear Proportioning) and the Bosch system on the 2009 and newer calls it EBD (Electronic Brake Distribution), but either one can handle minor variations in front/rear brake bias.

It's very common for track hounds to run a little more aggressive pad on the front than the rear (say, Carbotech XP12 on the front and XP10 rear, or Hawk DTC 70 front and DTC 60 rear), but in virtually all cases of different compounds, the more aggressive one is on the front.

In your case you want to run a much less aggressive pad on the front, and I agree with others that have recommended against that.

If you want to run a pad that doesn't stop as well, just go ahead and put them on both the front and rear.

Bob

StKnoWhere

"Shimmy" is often caused by pad imprinting resulting from a high speed stop. Never leave your foot on the brake pedal after you have used the brakes hard.

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

"The obvious question now is "is there a "cure" for discs with uneven friction material deposits?" The answer is a conditional yes. If the vibration has just started, the chances are that the temperature has never reached the point where cementite begins to form. In this case, simply fitting a set of good "semi-metallic" pads and using them hard (after bedding) may well remove the deposits and restore the system to normal operation but with upgraded pads. If only a small amount of material has been transferred i.e. if the vibration is just starting, vigorous scrubbing with garnet paper may remove the deposit. As many deposits are not visible, scrub the entire friction surfaces thoroughly. Do not use regular sand paper or emery cloth as the aluminum oxide abrasive material will permeate the cast iron surface and make the condition worse. Do not bead blast or sand blast the discs for the same reason.

The only fix for extensive uneven deposits involves dismounting the discs and having them Blanchard ground - not expensive, but inconvenient at best. A newly ground disc will require the same sort of bedding in process as a new disc. The trouble with this procedure is that if the grinding does not remove all of the cementite inclusions, as the disc wears the hard cementite will stand proud of the relatively soft disc and the thermal spiral starts over again. Unfortunately, the cementite is invisible to the naked eye."

NitrousMan

In one of the front rotors I can see and feel a very minor wave. I'm sure this is the source of my shimmy. Why shouldn't I turn the rotors? The pads that are on it look to be defective, half of the thin metal plate that cuts down on brake squeal appears to be missing like it was cut away during assembly. So now the back of the pad doesn't sit flush against the caliper piston causing the pad to wear in a wedge shape. Anyone else seen pads like this? Thanks.

fnsblum

I would suspect lateral run out. If you have a dial indicator check it yourself. If not take the rotors to your machine shop and have them checked. Later! Frank