Brake rotors get hot during braking. Usually the front rotors of cars are vented, with space between the two sides for air to flow and cool them off. For high performance applications, there are drilled rotors, with holes going through the rotor at regular intervals to aid in cooling and also to remove a little weight.
Most cars do not need drilled rotors, because the temperatures your brakes will reach during normal driving will not be that extreme. Some car owners, however, decide that they want to spend the extra money. These drilled rotors were on a Honda CR-V, which is far from a performance vehicle. Additionally, it’s a car that regularly sees snow and road salt, which don’t mix well with drilled rotors.
As you can see, the insides of the holes in rust, and the surface of gets even more rusted and uneven than it normally would. The brake pads are also unevenly worn because of the condition of the rotors. Even if there had been lots of life left on the pads, if this was my car I would change back to regular rotors and put in new pads. The rear pads on this car did need replacing, so at least one of the sets of drilled rotors is off this car.
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