Air Brakes CDL Test (2024) - FREE ME CDL Practice Test

1. The s-cam forces the brake shoes away from one another and presses them against the inside of the brake drum. It is called the s-cam because:

it applies a "Shock" to the brakes.
"S" stands for "Shoes".
it is shaped like the letter "S".

2. To make the brakes work, air brakes use:

3. The air compressor stops pumping air into the air storage tanks when air tank pressure rises to around:

4. To test the low pressure warning signal, you should:

shut the engine off when you have enough air pressure, turn the electrical power on and step on and off the brake pedal until the low air pressure warning signal comes on.
check the air hoses connected to the brake chambers to make sure they aren't cut.
pump the brakes while your vehicle is running.

5. Brake lag is:

the distance your vehicle will travel, in ideal conditions, while you are braking.
the amount of air pressure required to stop the vehicle.
the time required for the air brakes to work after the brake pedal is pushed.

6. Which of the following statements is true?

There is no way that short circuits due to damaged insulation can cause a vehicle fire.
Poor cargo ventilation is a common cause of fire.
Carrying a properly charged and rated fire extinguisher will help prevent fires.

7. The braking power of the spring brakes:

is not affected by the air pressure level.
depends on the brakes being in adjustment.
is not affected by the condition of the service brakes.

8. ABS brakes help you:

downshift before starting down a hill.
avoid wheel lock up.
lock up the wheels in an emergency stop.

9. What should you do to correct a drive-wheel braking skid?

Turn in the same direction as the skid.
Fully apply the brakes, turn the steering wheel quickly, push in the clutch, and countersteer.
Stop braking, turn the steering wheel quickly, push in the clutch, and countersteer.

10. With a fully-charged air system, the leakage rates should be less than:

2 psi for single vehicles and 3 psi for a combination of two vehicles.
5 psi for single vehicles and 10 psi for a combination of two vehicles.
3 psi for single vehicles and 4 psi for a combination of two vehicles.

AIR BRAKES PRACTICE TEST - MAINE