I'm about to install some slotted rotors on my car, and the insturctions say in bold NEW BRAKE PADS MUST BE USED WITH ROTORS Why is this? I have some fairly new pads on there... and I think they are worn just enough to make the installation of these thicker rotors a little easier?

 

Not only do they have to be new but also metallic pads.
(hawk pads)

David

 

Hmm.. I see, do you know why though? I'm just curious.. brakes aren't something i know a lot about.

 

Regular pads can't take the heat therefore they would end up
cracking your drilled & sloted rotors. metallic can with stand
a lot more heat then stock pads also theres less brake dust
from the metallic brake pads which is a plus. hope this helps.
GM brakes S U C K !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!
I was glad to up date my Zee with some SURE STOP rotors.

David

 

Ahh.. I see.. thanks for the help guys, I'll go pick up some new pads

 

As pads wear they become less flat. They develop high spots and low spots that show up as grooves in the pad or rotor. Its always recommended to replace pads and rotors as a set or use new pads with freshly turned rotors.