Instructions

Air Brakes

This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a test. The test consists of 25 multiple choice.. Read More

This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a test. The test consists of 25 multiple choice questions. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Florida CDL Handbook. Questions come from chapters covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.

Number of Question 25

Passing Score 20

19. Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:

Air pressure falls below 45 psi.

Air pressure falls below 20 psi.

Driving downhill.

Driving uphill.

Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.

20. The air storage tanks:

Hold only enough air for one braking cycle.

Hold enough air for brakes to be used several times if the compressor stops working.

Do not hold air unless there is an emergency.

Hold enough air for more than 1,000 braking cycles.

In an air brake system, the air storage tanks hold enough air for brakes to be used several times if the compressor stops working.

21. Service brakes should:

Be tested once a month.

Only be tested by a trained mechanic.

Be tested before every trip.

Before driving, you should always verify that your service brakes are in good working order. Testing the brakes before a trip allows you to locate any problems before you need to brake while on the road.

22. To confirm that a trailer has ABS, you can:

Look under the trailer for wheel speed sensors coming from the back of the brakes.

Look under the hood for the ABS sticker.

Look at the tires.

Remove a tire and look for the ABS sensor on the axle.

If you are unsure if a trailer is equipped with an Anti-Lock Braking System (ABS), look under the vehicle for the electronic control unit and wheel speed sensor wires coming from the back of the brakes.

23. Anti-Lock Braking Systems (ABS):

Reduce normal braking capacity.

Are equipped in addition to other braking systems and do not reduce normal braking power.

Are not effective on larger vehicles.

Are illegal in some states.

ABS is equipped in addition to a vehicle's normal braking system and it neither increases nor decreases the vehicle's braking capability. ABS activates during hard applications of the brake pedal in order to prevent wheels from locking up.

24. When leaving your vehicle unattended:

The parking brake should be used.

The parking brake only needs to be used if the vehicle is parked on a slope.

The parking brake should not be used, as it can damage the tires.

In general, you should always use the parking brake when parking your vehicle. However, you should not apply the parking brake if your brakes are very hot or if your brakes are wet and temperatures are below freezing.