CDL Airbrakes Practice Test 2

Question 1

What is the primary purpose of a front brake limiting valve?

Accepted Answer

Answer

Improves the stopping ability of the vehicle

Answer

Cuts the air pressure to the front brakes by half

Answer

Detects road conditions and switches from slippery to normal as necessary

Answer

Increases the stopping ability of the rear brakes

Question 2

Which of the following will affect the stopping power of spring brakes?

Accepted Answer

All of the above

Answer

Road conditions

Answer

Proper adjustment

Answer

Modulating control valve position (if equipped)

Question 3

A dual air brake system has which of the following features?

Accepted Answer

One set of brake controls and two separate air brake systems

Answer

Two sets of brake controls and two separate air brake systems

Answer

Two sets of brake controls and one air brake system

Answer

One set of brake controls and one air brake system

Question 4

Where are foundation brakes used?

Accepted Answer

On all wheels

Answer

In emergency situations

Answer

On front axles only

Answer

When parking

Question 5

Which of the following parts of the air brake systems should be checked during the pre-trip walk around inspection?

Accepted Answer

All of the above

Answer

Slack adjusters on S-cam brakes

Answer

Air hoses connected to the brake chambers

Answer

Brake discs or drums

Question 6

During inspection, if a slack adjuster moves less than about one inch where the push rod attaches to it, which of the following statements is true?

Accepted Answer

It has the appropriate amount of slack

Answer

It will fail roadside inspections

Answer

It probably needs adjustment

Answer

The vehicle will be very hard to stop

Question 7

When testing the air leakage rate (by turning off the engine and releasing the parking brake), what is an acceptable air loss rate?

Accepted Answer

Less than 2 psi in one minute for single vehicles and less than 3 psi in one minute for combination vehicles.

Answer

Less than 3 psi in one minute for both single and combination vehicles

Answer

Less than 3 psi in one minute for single vehicles and less than 2 psi in one minute for combination vehicles.

Answer

Less than 2 psi in one minute for both single and combination vehicles

Question 8

Which of the following is not a step in testing that the spring brakes come on automatically?

Accepted Answer

Pull out the parking brake control knob

Answer

Release parking brake

Answer

Pump the brake pedal repeatedly

Answer

Shut the engine off

Question 9

If you use controlled braking, which of the following is an acceptable procedure?

Accepted Answer

Release the brakes if you need to make a large steering adjustment

Answer

If you need to turn, keep the brakes applied

Answer

Apply the brakes all the way to lock the wheels

Answer

If your wheels start sliding, press the brake harder

Question 10

What should you do if the low air pressure warning light comes on?

Accepted Answer

Stop and safely park your vehicle as quickly as possible

Answer

Drive to the nearest service station

Answer

Use stab braking until you are stopped

Answer

No immediate action is required