When should brake rotors be resurfaced?

Brake rotors should be resurfaced when they have a slight warping. Warped rotors can lead to uneven contact between the brake pads and the rotor surface, which can result in vibrations and reduced braking performance. Resurfacing helps restore a flat surface on the rotor, ensuring that the brake pads can make consistent contact, improving braking efficiency and vehicle safety.

When considering the conditions for resurfacing rotors, it's essential to note that while rust can be cleaned off, it does not inherently mean that resurfacing is necessary. Additionally, if rotors are below the minimum thickness specified by the manufacturer, they must be replaced rather than resurfaced, as this is crucial for maintaining structural integrity and performance during braking. A humming noise indicates potential issues but is not a specific indicator that resurfacing is required, as it could result from other components in the braking system. Thus, slight warping is a clear and direct condition that justifies resurfacing the rotors to maintain optimal brake functionality.