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Practice test 3 of 10

Illinois CDL — Air Brakes Practice Test 3

The Illinois 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.If one half of a dual air brake system loses most of its pressure, what is the result?
  2. 2.If a truck's air compressor is built with its own oil supply, what should you do before driving?
  3. 3.With manually operated drain valves, how often are you responsible for emptying the tanks?
  4. 4.What is a modulating control valve used for?
  5. 5.On which tank is the safety relief valve, set to open near 150 psi, installed?
  6. 6.You find you must keep increasing application pressure to hold a steady speed. What does this most likely indicate?
  7. 7.Which brake defect turns up most often during roadside inspections?
  8. 8.Which of the three air brake systems do you operate with the foot pedal during everyday driving?
  9. 9.On some buses, what does a separate air tank tied to a dual parking control valve allow?
  10. 10.While you are driving normally, what keeps the strong springs of the spring brakes from applying the brakes?

0 of 25 answered