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Practice test 4 of 10

Washington CDL — Air Brakes Practice Test 4

The Washington CDL — Air Brakes knowledge test has ~25 questions; you need ~20 correct (80%) to pass.

This practice test follows that format: 25 questions, pass with 20 correct. Answer every page, then grade it to see the answers and explanations.

Questions 1–10 of 25

  1. 1.What does a supply pressure gauge tell the driver?
  2. 2.Why is needlessly pumping the brake pedal on and off a dangerous habit in an air brake vehicle?
  3. 3.If the air compressor carries its own oil supply, what should the driver do before setting out?
  4. 4.Using the recommended braking technique on a long downgrade, once you are in the proper low gear you should do what?
  5. 5.How large a crack in a brake drum makes it unfit for service during inspection?
  6. 6.Before driving a dual-air vehicle, you should let pressure build to at least what level in BOTH systems?
  7. 7.What is the purpose of a modulating control valve for the spring brakes?
  8. 8.When you press the pedal on an s-cam brake, what does the s-cam itself do?
  9. 9.In an air-operated disc brake, what part takes the place of the s-cam?
  10. 10.How can brakes that are out of adjustment lead to a loss of braking on a long hill?

0 of 25 answered