This month’s pop quiz addresses Brake Rotors. Choose the answer that best completes the following statements or questions.
Solution to the Pop Quiz follows below – Scroll down. Answers are in bold.
1) The vehicle owner may say that under light braking the vehicle pulses to a stop, or under heavy braking the vehicle shudders. Technical service bulletins (TSBs) often describe these symptoms as a _________ .
A. “judder” B. “twitter” C. “stumper” D. “studder”
2) If rotors with a different rib design or configuration are installed, it may create cooling and/or noise problems. In fact, if an OEM rotor has 37 ribs and an economy rotor has only 32, cooling may be reduced __________ .
A. 2%-3% B. 4%-7% C. 8%-10%. D. 30%-40%
3) The latest OEM service specifications typically call for ___________ of lateral runout, which can be measured by placing a dial indicator against the face of the rotor and turning the rotor.
A. 1.2- to 2.2-inch B. 0.1- to 0.2-inch C. 0.001- to 0.003-inch D. 0.03- to 0.09-inch
4) If you see more than the allowed amount of movement in the dial indicator, the rotor and/or hub may have too much ________ which will eventually cause brake judder.
A. burnout B. fallout C. runout D. rollout
5) A rotor must be replaced if it’s worn down to minimum specifications or the ________, or cannot be resurfaced without exceeding the minimum “machine to” spec.
A. discard thickness B. groove requirement C. checked point D. thickness quotient
6) Rotor thickness is measured with a ____________ .
A. ammeter B. scaleometer C. runout wedge D. micrometer
7) Some rotor manufacturers will research and formulate high temperature and high strength alloys in order to have the best ___________ microstructures.
A. friction B. metallurgical C. grit D. bilateral
8) When installing new rotors, verify that the hub is clean and run-out is within specifications. The ___________ runout is magnified at the rotor friction surface.
A. surface B. flange C. diameter D. thickness
Answers below. Scroll down
1) The vehicle owner may say that under light braking the vehicle pulses to a stop, or under heavy braking the vehicle shudders. Technical service bulletins (TSBs) often describe these symptoms as a _________ .
A. “judder” B. “twitter” C. “stumper” D. “studder”
2) If rotors with a different rib design or configuration are installed, it may create cooling and/or noise problems. In fact, if an OEM rotor has 37 ribs and an economy rotor has only 32, cooling may be reduced __________ .
A. 2%-3% B. 4%-7% C. 8%-10%. D. 30%-40%
3) The latest OEM service specifications typically call for ___________ of lateral runout, which can be measured by placing a dial indicator against the face of the rotor and turning the rotor.
A. 1.2- to 2.2-inch B. 0.1- to 0.2-inch C. 0.001- to 0.003-inch D. 0.03- to 0.09-inch
4) If you see more than the allowed amount of movement in the dial indicator, the rotor and/or hub may have too much ________ which will eventually cause brake judder.
A. burnout B. fallout C. runout D. rollout
5) A rotor must be replaced if it’s worn down to minimum specifications or the ________, or cannot be resurfaced without exceeding the minimum “machine to” spec.
A. discard thickness B. groove requirement C. checked point D. thickness quotient
6) Rotor thickness is measured with a ____________ .
A. ammeter B. scaleometer C. runout wedge D. micrometer
7) Some rotor manufacturers will research and formulate high temperature and high strength alloys in order to have the best ___________ microstructures.
A. friction B. metallurgical C. grit D. bilateral
8) When installing new rotors, verify that the hub is clean and run-out is within specifications. The ___________ runout is magnified at the rotor friction surface.
A. surface B. flange C. diameter D. thickness
