Skip to main content
DMV Test Free
ENES

Practice test 1 of 10

Texas CDL — Air Brakes Practice Test 1

The Texas 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.Unlike hydraulic brakes, air brakes have brake lag. About how long does it take air to flow through the lines and work the brakes after you press the pedal?
  2. 2.What job does an alcohol evaporator perform in some air brake systems?
  3. 3.If a leak drains all the air out of the brake system while you drive, what physically applies the spring brakes?
  4. 4.You are parking a vehicle whose spring brakes are applied with a modulating control valve on the dash. How do you set it?
  5. 5.On newer air-braked vehicles the parking brake control is a yellow, diamond-shaped knob. On older vehicles, what might it look like instead?
  6. 6.Which part of an air brake system pumps the compressed air that the brakes depend on?
  7. 7.The yellow ABS malfunction lamp stayed lit after the start-up bulb check and is still on as you cruise down the highway. What does that tell you?
  8. 8.Which list correctly names all the parts of total stopping distance for a vehicle with air brakes?
  9. 9.Why is it a bad habit to press and release the brake pedal over and over when you don't need to?
  10. 10.You are stab braking in an emergency. After the wheels lock and you release the pedal, when do you apply the brakes fully again?

0 of 25 answered