nice write up gonna add few advice on how to replace brake pads. In general, brake rotors should be re-surfaced when you replace the pads. As brakes wear down, the surface of the rotor will become worn as well, and will not be even. Re-surfacing restores the rotor surface to a smooth, flat, uniform finish - which is a nice match for the new, flat brake pads. However, re-surfacing removes metal (it essentially removes all of the high spots until the whole surface is even with the lowest spot previously found). This will result in the brake rotor being thinner than when the car was new. All brake rotors have a specification for minimum thickness.