Which of the following indicates that a brake rotor needs resurfacing or replacement?

A brake rotor needing resurfacing or replacement can be identified by specific signs indicating wear or damage. The presence of visual scratches on the rotor surface is a clear indicator that the rotor has been subjected to excessive wear or contamination, and this can compromise the braking performance. It is essential to address these scratches, as they can reduce the contact area with the brake pads and lead to further braking issues.

Additionally, if the thickness of the rotor is below the manufacturer specifications, this is a significant concern. Manufacturers set specific thickness standards to ensure effective heat dissipation and structural integrity. When the rotor wears beyond these specifications, it risks becoming warped or cracking, which can severely affect braking performance, increase stopping distances, and contribute to a dangerous situation.

Consequently, both visual scratches and insufficient rotor thickness denote that the rotor should be resurfaced or replaced to maintain safety and performance standards. Therefore, recognizing these two indicators is crucial for appropriate brake maintenance and ensuring the vehicle remains safe to operate.