Practice question

For the Washington CDL Air Brakes knowledge test, why are S-cam, disc, and wedge brakes generally similar in basic function?

  1. They all use hydraulic fluid
  2. All three convert air pressure into mechanical force that applies friction material against a drum or rotor — they differ mainly in the mechanism
  3. They all use hydraulic master cylinders
  4. They all are mechanical only

Answer: B — All three convert air pressure into mechanical force that applies friction material against a drum or rotor — they differ mainly in the mechanism

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