TT April '09 Pop Quiz: Rotors
4/24/2009
This month’s pop quiz addresses brake rotors. Choose the answer that best completes the following statements or questions.
This month’s pop quiz addresses brake rotors. Choose the answer that best completes the following statements or questions.
For the answers to the Pop Quiz, scroll down beyond the questions.
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 OE 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 ________ for smooth braking.
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, check the hub __________ runout. The ___________ runout is magnified at the rotor friction surface.
A. surface B. flange C. diameter D. thickness
NOTE: Answer Key Below - Scroll down:
Solutions in bold
TT Pop Quiz: Rotors
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 OE 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 ________ for smooth braking.
A. burnout B. fallout C. runout D. rollout
5. A rotor must be replaced if it’s worn down to minimum specifications or the ________ discard thickness, 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, check the hub __________ runout. The ___________ runout is magnified at the rotor friction surface.
A. surface B. flange C. diameter D. thickness