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Practice test 4 of 10

South Carolina CDL — Air Brakes Practice Test 4

The South Carolina 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.When checking manual slack adjusters on s-cam brakes, how much movement suggests the brakes probably need adjustment?
  2. 2.Where would you look for the ABS malfunction lamp on a trailer?
  3. 3.What causes brake fade?
  4. 4.On older vehicles with a front brake limiting valve, what happens when the cab control is set to 'slippery'?
  5. 5.The governor lets the compressor start pumping again at the 'cut-in' pressure. About what pressure is that?
  6. 6.Where is the safety relief valve located, and at about what pressure is it usually set to open?
  7. 7.Total stopping distance for an air brake vehicle is made up of four parts. Which set lists them correctly?
  8. 8.In a dual air system, when should the low air pressure warning come on?
  9. 9.Why is it important to drain the air tanks regularly?
  10. 10.Vehicles built since which year come equipped with automatic slack adjusters?

0 of 25 answered