Question

Technician A states that on modern cars thickness variation should not exceed .002 in. Technician B states that a rotor installed with over specification runout may not be immediately felt as a pedal pulsation. Who is correct?

Answer 1

Both Technician A and Technician B are correct. Thickness variation on car rotors should not exceed 0.002 inches, and rotor runout that exceeds specifications may not initially cause a noticeable pedal pulsation but can lead to issues over time.

Step-by-step explanation:

The question pertains to the acceptable thickness variation and rotor runout specifications for modern cars. Technician A is correct that thickness variation on modern car rotors should not exceed 0.002 inches. This is a critical tolerance to ensure smooth braking and prevent issues such as brake pulsation or vibration. Technician B's statement is also accurate as a rotor that is installed with runout exceeding specifications may not immediately result in a noticeable pedal pulsation. It is possible that the effects of excessive runout could become more apparent over time as the rotor wears unevenly, potentially leading to brake pedal pulsation or other braking performance issues.