Skip to main content
DMV Test Free
ENES

Practice test 2 of 10

Missouri CDL — Air Brakes Practice Test 2

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.Why do air brakes have 'brake lag' that hydraulic brakes do not?
  2. 2.The low air pressure warning must come on before tank pressure falls below what level?
  3. 3.In a dual air system at operating rpm, pressure should climb from 85 to 100 psi within about how long?
  4. 4.On the application pressure gauge, needing more pressure to hold the same speed usually means what?
  5. 5.How large a crack in a brake drum is unacceptable during inspection?
  6. 6.With a dual air system, how much pressure should you build up in each system before you start driving?
  7. 7.How often must you empty air tanks fitted with manually operated drain valves?
  8. 8.The safety relief valve in the first air tank is usually set to open at what pressure?
  9. 9.If one part of a dual air system loses most of its pressure, what is the result?
  10. 10.What slows the vehicle when the shoes press against the drum, and what byproduct results?

0 of 25 answered