If you've just installed a big brake kit or even if you've only changed your brake pads and rotors, you should "bed" them in by following the instructions below. Proper bedding of brakes will improve pedal feel, reduce or eliminate brake squeal, and extend the life of your pads and rotors. Because bedding increases the emissivity of the rotors, it even allows them to shed more heat via radiation, making them run cooler. For more on the theory of bedding, please refer to this excellent article by StopTech: Removing the Mystery from Brake Pad Bed-In.
Caution: When you've just installed new pads/rotors or a big brake kit, the first few applications of the brake pedal will result in almost no braking power. Gently apply the brakes a few times at low speed in order to build up some grip before blasting down the road at high speed. Otherwise, you may be in for a nasty surprise the first time you hit the brakes at 60 mph.
When following these instructions, please avoid doing it in the presence of other vehicles. Breaking in your new pads and rotors is often best done very early in the morning, since other drivers will have no idea what you are up to and will respond in a variety of ways ranging from fear to curiosity to aggression. And an officer of the law will probably not understand when you try to explain why you were driving erratically! Zeckhausen Racing does not endorse speeding on public roads and takes no responsibility for any injuries or tickets you may receive while following these instructions.
From a speed of about 60mph, gently apply the brakes to slow the car down to about 45mph, then accelerate back up to 60mph and repeat. Do this about four or five times to bring the brakes up to operating temperature. This prevents you from thermally shocking the rotors and pads in the next steps.
Make a series of eight near-stops from 60 to about 10 mph. Do it HARD by pressing on the brakes firmly, just shy of locking the wheels or engaging ABS. At the end of each slowdown, immediately accelerate back to 60mph. DO NOT COME TO A COMPLETE STOP! (Note: With less aggressive street pads and/or stock brake calipers, you may need to do this fewer times. If your pedal gets soft or you feel the brakes going away, then you've done enough. Proceed to the next step.)
During this process, you must not come to a complete stop because you will transfer (imprint) pad material onto the hot rotors, which can lead to vibration, uneven braking, and could even ruin the rotors.
Depending on the pads you are using, the brakes may begin to fade slightly after the 7th or 8th near-stop. This fade will stabilize, but not completely go away until the brakes have fully cooled. A bad smell from the brakes, and even some smoke, is normal.
After the 8th near-stop, accelerate back up to speed and drive around for as long as possible without using the brakes. The brakes will need at least 10 minutes to cool down. Obviously, it's OK to use the brakes to avoid an accident, but try to minimize their use until they have cooled.
If club race pads, such as Pagid Orange or Porterfield R4, are being used, add four near-stops from 80 to 10mph. If full race pads, such as Pagid Black, are being used, add four near-stops from 100 to 10 mph.
After the break-in cycle, there should be a blue tint and a light gray film on the rotor face. The blue tint tells you the rotor has reached break-in temperature and the gray film is pad material starting to transfer onto the rotor face. This is what you are looking for. The best braking occurs when there is an even layer of of pad material deposited across the face of the rotors. This minimizes squealing, increases braking torque, and maximizes pad and rotor life.
After the first break in cycle shown above, the brakes may still not be fully broken in. A second bed-in cycle, AFTER the brakes have cooled down fully from the first cycle, may be necessary before the brakes really start to perform well. If you've just installed a big brake kit, the pedal travel may not feel as firm as you expected. After the second cycle, the pedal will become noticeably firmer.