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Practice test 4 of 10

Missouri CDL — Air Brakes Practice Test 4

The Missouri 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.In the recommended downgrade braking pattern, once your speed is about 5 mph below your safe speed, what do you do?
  2. 2.The total stopping distance for an air brake vehicle is made up of which four parts?
  3. 3.At about what pressure do a tractor or straight truck's spring brakes fully engage on their own?
  4. 4.When the low air warning light and buzzer first come on, what should you do?
  5. 5.Why is draining the air tanks important?
  6. 6.What does an antilock braking system (ABS) do during hard braking?
  7. 7.What does it likely mean if the yellow ABS malfunction lamp stays lit after the start-up bulb check?
  8. 8.During ordinary driving, what does the service brake system do?
  9. 9.In a dual air system at operating rpm, pressure should climb from 85 to 100 psi within about how long?
  10. 10.How do spring brakes hold the vehicle when the air pressure is lost?

0 of 25 answered