Had my brakes done and see an item on my bill for "Grinding Disc" - what's this for?
Resurfacing the brake rotors is standard when doing brakes.
This is different than normal brake lathe, it is a machine that actually uses grinding wheels on both sides of the rotor while it is still mounted on the vehicle, makes a better pattern for seating in new pads plus it surfaces the the entire braking area on both sides in one sitting. But there must be enough metal on the rotors for this to work properly or the rotors will warp really fast. Personally I think it’s just another way to up the price with a new way of doing what has been done for decades.