Is there a mechanical test? This mechanic drives the car and tells me warped rotor(s). But it's too hard to tell which one or how many by driving it, he says. So, now I must remove and resurface all the rotors based on a braking shimmy. This just doesn't sound right to me. Couldn't the mechanic determine if a rotar was warped by running a micrometer around it? If so, would he have to remove it first or could he do it while still on the car?