Editing Disc brake (section)

===Disc damage modes===
{{Unreferenced section|date=January 2016}}

Discs are usually damaged in one of four ways: scarring, cracking, warping, or excessive rusting. Service shops will sometimes respond to any disc problem by changing out the discs entirely, This is done mainly where the cost of a new disc may be lower than the cost of labor to resurface the old disc. Mechanically this is unnecessary unless the discs have reached the manufacturer's minimum recommended thickness, which would make it unsafe to use them, or vane rusting is severe (ventilated discs only). Most leading vehicle manufacturers recommend brake disc skimming (US: turning) as a solution for lateral run-out, vibration issues, and brake noises. The machining process is performed in a brake [[lathe]], which removes a very thin layer off the disc surface to clean off minor damage and restore uniform thickness. Machining the disc as necessary will maximize the mileage out of the current discs on the vehicle.