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Practice test 4 of 10

Mississippi CDL — Air Brakes Practice Test 4

The Mississippi 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.Your truck has a brake system failure. To bring it to a stop, the emergency brake system relies on parts of which other systems?
  2. 2.At operating rpm, your dual air truck with standard-size tanks takes about two minutes to climb from 85 to 100 psi. What does that tell you?
  3. 3.You are warming up a large bus, and its low pressure warning signals at about 80 psi, well above 55. What does the manual say about this?
  4. 4.A mechanic says the air disc brakes on your truck work like a big c-clamp. Which part, turned by the slack adjuster, does the clamping?
  5. 5.If your service brakes fail, how can a modulating control valve help you stop?
  6. 6.If the low air warning signal does not work, what could happen in a single-circuit air brake system?
  7. 7.Which statement about automatic air tank drains is accurate?
  8. 8.During the final air brake check, with the engine idling, how do you lower tank pressure to see whether the compressor cuts back in?
  9. 9.A bus has lost its main air pressure, and you are holding in the spring-loaded button of its dual parking control valves to move it. What happens when you let go?
  10. 10.You are driving an air-braked truck at 55 mph on dry pavement when you spot a hazard. With good traction and brakes, about how much road will you cover from seeing it to stopping?

0 of 25 answered