Final answer:
To measure rotor lateral run-out, one would use a dial indicator or a rotor run-out gauge to obtain precise readings of the rotor's deviation from its true rotational axis.
Step-by-step explanation:
The tools used to measure rotor lateral run-out include a dial indicator and a rotor run-out gauge. These instruments allow for precise measurements of the deviation of the rotor from its true rotational axis. Rotor run-out can lead to vibrations and uneven brake pad wear, making accurate measurement crucial for vehicle maintenance and safety. Typically, the dial indicator is mounted on a fixed point relative to the brake assembly, and its probe is set against the rotor's surface. As the rotor is turned, the dial indicator provides a reading of the lateral displacement, helping mechanics to determine if the rotor is within the acceptable tolerance or if it requires correcting or replacement.