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Montana CDL — Air Brakes Practice Test 1

The Montana 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.The manual says the low air pressure warning must come on before tank pressure falls below 55 psi. What alternative figure does it give for older vehicles?
  2. 2.A driver wants a passenger endorsement and will drive a bus that has air brakes. Besides the test on Sections 2 and 4, what does the manual say this driver must also pass?
  3. 3.During a trip you find that the safety relief valve on the first air tank has been releasing air. How does the manual treat that?
  4. 4.In a wedge brake, what does the brake chamber push rod do?
  5. 5.The governor cut the compressor out at about 125 psi. After several brake applications the gauge reads 110 psi and is still dropping. Going by the manual's typical figures, what is the compressor doing?
  6. 6.Before checking slack adjusters on s-cam brakes, the manual has you chock the wheels on level ground and then release the parking brakes. Why release them?
  7. 7.Air pressure has leaked down until the spring brakes apply on a heavily loaded truck. Why does the manual say the stop will be a long one?
  8. 8.In the air leakage rate test on the vehicle inspection test, you shut off the engine, release the brakes and press the foot brake all the way down. When does the manual's one-minute count begin?
  9. 9.How does the manual say a manually operated air tank drain valve is worked?
  10. 10.An air disc brake has a brake chamber and a slack adjuster, just as an s-cam brake does. Which part does the manual say takes the place of the s-cam?

0 of 25 answered