So you have successfully replaced your brake pads -- along with the rotors, if needed -- and your ready to call it a day, but if you think the job is done you couldnt be more mistaken. You may have fresh pad and rotors, but you must burnish the brake pads so that an even layer of pad material is transferred to the surface of the rotors, otherwise you could end up with a slight jitter or vibration when you apply the brakes. Burnishing your brake pads is a pretty simplistic process and is also known as brake pad break-in or new pad conditioning.
The purpose
The purpose of burnishing is to prepare the brake system for optimal efficiency and comfort. Burnishing is a multi-step process that has to be performed properly to be effective. Failure to follow the process correctly will slowly build up an uneven layer of pad material on the brake rotor, causing your vehicle to develop a pulse or vibration anytime the brakes are applied.
What Happens
In a nut shell, you drive the vehicle and perform several light stops to thoroughly and evenly heat the brake pads and rotors. Once the brakes are sufficiently warmed, you will repeatedly perform more aggressive braking at a higher speed without stopping followed by a brief sustained driving period to allow the brakes to cool evenly. As the process is completed, a very fine, even layer of pad material is transferred to the rotors, allowing your brakes to perform at their best when the time comes.
The Effects on the Pad
It is commonly thought that burnishing the brakes would cause quick brake wear or eat up a large portion of the brake material at an early stage in the pads' life. While these concerns may seem completely logical due to the initial rough use of the pad, the amount of material that is transferred from pad to rotor is actually very little. It is actually more important to know how to burnish brakes properly than it is to know what it does or why. Improper burnishing procedures could overheat the pads or not heat them evenly, causing an uneven initial wear. Keep in mind that it doesnt create a lot of danger if the pads wear unevenly at first, but the effects will be annoying and could cause your pads to wear out sooner than normal. When you replace your pads and perform the procedure you should always use OEM, or factory-replacement, style brake pad utilizing the pad material; in other words, dont replace stock ceramic pads with a cheap semi-metallic pad, if at all possible.
Proper Technique
There is a lot of speculation around what is actually the proper procedure to burnish new brakes. Truth is, it really depends on the brake pad and the vehicle they are on. Larger and smaller surfaces will create different amounts of heat, as will different pad materials. A good rule of thumb is to perform about 10 stops from between 20 and 30 miles per hour. Repeat the procedure, but be within the speed range of 35 to 45 miles per hour for the second set of braking runs. Continuously drive for the next 10 to 15 minutes to allow the system to completely cool. You always want to use a steady foot without dragging the brakes; apply firm pressure against pedal until the vehicle stops and immediately continue to the next stop, but do not lock up the brakes. Never attempt to perform this procedure on the road and always use a spot where you can safely accelerate and stop in this fashion; a large empty parking lot is ultimately best.
