Just wanted to know what causes brake rotors to be scored badly?

crappy brake bads? crappy rotors? i have no idea what i have the previous owner put all the stuff on.

 

There are probably a range of causes, but I quickly destroyed a set of rotors on the track by running hard with new brake pads. I skipped the bed-in procedure and learned a valuable lesson. I always bed the pads in now before I push them hard. The rotors were deeply grooved and cracked up horribly.

-Max

 

could you elaborate on the bed-in procedure?

TIA,
LDawg

 

It depends on the pad, but normally you just do some increasingly heavy braking and then let the car sit for a while (30 minutes or something). Hawk track pads usually come with a little card with instructions. Brake from 60-20 a few times and then end up with a few hard 80-20 stops before you let it sit. I don't think it is an exact science, but don't slap new pads on and start running hot laps right away. It would probably be okay to install new pads and then drive to the track to bed them.

Another tip is that some pads have incompatible transfer layers on the rotor. If you switch pad types (ferro-carbon to carbon-kevlar, for instance) you might need to allow extra bedding time, or clean the old transfer layer off the rotor before the install. Do a little work with some sandpaper or get the rotors turned to remove the old layer. PFC pads lay down a very tough transfer layer, so you should keep using PFC pads or get the rotors turned if you switch to another pad. If you switch to track pads at the track, try to find street and track pads that are compatible -- two pads from the same manufacturer are probably your best bet.

-Max