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Practice test 3 of 10

Iowa CDL — Air Brakes Practice Test 3

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.Four drivers each report one result from their final air brake checks. Which result is within what the manual expects?
  2. 2.To get credit for the air brake check on Iowa's pre-trip vehicle inspection test, what must you do?
  3. 3.During the final air brake check, you idle the engine and fan the brake pedal. The gauge falls through 100 psi, then 90, then 80, and never starts climbing again. What has the check revealed?
  4. 4.Which statement about the air compressor does NOT match the manual?
  5. 5.Which pairing of a parking situation with what the manual tells you to do is correct?
  6. 6.Four different rigs each lose 2.5 psi in one minute during their pre-trip air leakage checks, all with the engine off. Which rig should stay parked until the leak is found and fixed?
  7. 7.In Iowa's air brake check, you have just finished the leakage test. What should you do about the engine before starting the low air warning test?
  8. 8.During the engine-area fluid check on Iowa's inspection test, which fluid on the list applies only to vehicles with hydraulic brakes, not air brakes?
  9. 9.A driver figures that since his truck has working ABS, a couple of brakes running a little out of adjustment won't hurt his stops. Why is he wrong?
  10. 10.In the final air brake check, your governor stops the compressor at about 130 psi rather than 125. What does the manual say about the exact cut-out point?

0 of 25 answered