Air Brakes CDL Test - FREE Louisiana CDL Practice Test

1. To check slack adjusters on S-cam brakes, you should:

use gloves and pull hard on each slack adjuster you can reach.
press the brake pedal and listen for any strange noises.
check that the spring brakes come on automatically.
All of the above.

2. The safety valve installed in the first tank the air compressor pumps air is set to open:

every 15 minutes.
if there is too much pressure.
if there is too little pressure.
at 30 psi.

3. When should you be particularly careful about high winds?

4. To operate a vehicle equipped with air brakes, you must pass the air brakes knowledge test. Why?

If you don't pass the air brakes test, you can't get a CDL.
All trucks have air brakes.
If you don't, you will only receive a CDL permit.
If you don't pass the air brakes test, you will be restricted to driving vehicles without air brakes.

5. You are coming down a long, steep downgrade. Which of the following is a sign that your brakes may have started to fade?

The steering feels heavy.
The brake pedal feels spongy or goes to the floor.
You have to apply your brakes harder and harder to get the same stopping power.
You hear a loud "bang".

6. Foundation brakes are used:

7. The safety relief valve is located:

in the first tank the air compressor pumps air to.
on the dashboard.
on each end of the vehicle's axles.
in the front brake.

8. The safety valve is usually set to open at:

9. Air tanks must be drained because:

if one air system is low on pressure, the rear brakes will not be operating fully.
when you push the brake pedal, air is let into each brake chamber.
if you don't drain the tanks yourself, your battery fluid may drain out.
compressed air usually has some water in it. The water can freeze in cold weather and cause brake failure.

10. With brake drums, if brakes become too hot:

the air compressor will kick on to cool the brakes.
your ABS will malfunction.
the brakes may stop working.
the brakes will supply too much power to the drive wheels.

LA CDL AIR BRAKES PRACTICE TEST