Skip to main content
DMV Test Free
ENES

Practice test 5 of 10

Iowa CDL — Air Brakes Practice Test 5

The Iowa 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.While you're driving, a mechanical arm suddenly swings down into your view. What has happened?
  2. 2.Your truck's air compressor is driven by gears off the engine rather than by a belt. How does that change the air brake check in the engine compartment step?
  3. 3.Most of the final air brake check is done with the vehicle standing still. Which part of it has you drive the vehicle forward?
  4. 4.You take Iowa's air brake check in a truck towing a trailer that has no air brakes. Which leakage standard does the manual apply?
  5. 5.Which statement about the air compressor does NOT match the manual?
  6. 6.A heavily loaded truck loses its air to a leak, and the spring brakes come on. Why will it need a long distance to stop?
  7. 7.When you inspect the air and electric lines between a tractor and trailer on Iowa's test, which check applies only to air brake systems?
  8. 8.On Iowa's inspection test, you check the air lines between the power unit and an air-braked trailer. What does the manual say a low air condition can do to the trailer?
  9. 9.You're using controlled braking in an emergency in a truck without ABS, and the wheels lock. What does the manual tell you to do?
  10. 10.Several parts of the final air brake check are done with the engine shut off. Which of these checks is done with the engine running?

0 of 25 answered