Good Q&A About Plugged Rotors
 

Question:

Took my car in for an oil change and the invoice came back with the following note on it:
"Ownwer advised that the vehicle will be in need of replacement front and rear brake pads and wear sensors by next service. Also notified that drilled rotors are plugged with brake material and debris which need to be drilled and dressed."

My question does not concern the potential need for pad repalcement. I have the factory workshop manuals and they are very specific about required pad thickness. I am wondering about this "plugging" situation. The car has never been tracked or autocrossed. Is this something that is routinely seen, and what is the proscribed cure for it?

Answer:

The reason that the rotors are plugging is do to the temperature that the pads are heating up to. Your day to day driving habits must be fairly aggressive or you ride with your foot on the brake. This is often seen in cars that are brought to DE events and the stock pads are being used. What happens is the pads literally starts to soften to a point they become pliable on there surface contact to the rotor. This now allows the pad material to plug the holes in the rotors. You can clean out the holes as long as the rotors are not warped or under their minimum thickness, otherwise replace them.
Now as far as a cure you will either have to lighten up in your driving or go to a more aggressive pad. This will have an advantage and a disadvantage. The advantage is that the filling of the rotors will be cut down or even stopped. The disadvantage is that the harder the pad the more time it takes to heat them up for normal street use. A stock pad is soft enough to stop the car immediately when applied. A race pad at the other end of the spectrum would most likely cause you to hit what you where trying to avoid until heated up.
Scott Slauson - PCA WebSite - 1/29/2006

Definately learned something new...I guess it is the cheese grater effect? Do you know how many miles you had on tge brake pads (rough estimate)?

Rail26, I don't know. This was a post I saw on the PCA web site, and thought that I would share with the forum.

I knew that. :o

I have drilled Zimmerman rotors and have never been told this nor have observed this.

What rotors do you have??

How much were your Zimmermans?

Did you notice any performance improvement?

At what mileage did you replace them? Out of necessity or just because cross-drilled looks cool?

Hi,

Drilled Rotors on a Street Car which is not Tracked, Auto-X'd, or DE'd is purely an aesthetic enhancement. No real benefit, or extremely little, is derived from them because you are not using the Brakes Hard enough, or Frequently enough, to worry about Fade due to a build-up of Plasma between the Pad and the Rotor.

The Trade-off to aesthetics are accelerated wear to the Pads (especially Street formulated ones) and Stress Cracks in the Disc, possibly leading to early replacement. I don't use them...

Happy Motoring!... Jim'99

Hi Socratic and Rbennett:

I am sorry if I missled you. I can't answer your questions. I saw this posting on the PCA Tech Website, and thought I woud share it with our forum, in hopes it would be informative to other members.