MISSOURI CDL AIR BRAKES TEST
CORRECT 100%
An anti-lock braking system (ABS)
A - increases your normal braking capability
B - decreases your normal braking capability
C - activates when your wheels are about to lock up
D - shortens your stopping distance - ANSWER C - activates when your wheels are
about to lock up
Which of the following are true about a dual air brake system?
A - usually, one system operates the front axle and the other one operates the rear axle
B - one system is called the "primary" system and the other one is called the
"Secondary" system
C - it uses a single set of brake controls
D - all of the above are true - ANSWER D - all of the above are true
Which of the following is NOT part of the air brake system?
A - Radio signal system
B - Parking brake system
C - Service brake system
D - Emergency brake system - ANSWER A - Radio signal system
Which of the following will be true about your brake function if your anti-lock braking
system (ABS) fails?
A - it may cause problems with other mechanical systems and possibly pose a huge fire
risk
B - you will have no brake function and your truck will be out of control
C - it will slow your truck to a halt and force you to pull over
D - you will still have normal brake function and will just need to get the ABS repaired
soon - ANSWER D - you will still have normal brake function and will just need to get
the ABS repaired soon
At what measurement is the safety valve USUALLY set to open?
A - 150 PSI
B - 200 PSI
C - 250 PSI
D - 100 PSI - ANSWER A - 150 PSI
, Spring brakes are
A - made up of powerful springs that are held back by air pressure while you are driving
B - not going to take full effect until your PSI drops to a certain range, typically 20 to 30
PSI
C - brakes that come on automatically on a truck or tractor when the PSI drops too low
D - all of the above - ANSWER D - all of the above
The tractor protection valve
A - will close if you apply the parking brakes
B - provides the air supply for the brake system
C - will close automatically if the air supply drops to a certain level
D - does all of the above - ANSWER D - does all of the above
Slack adjusters are
A - part of the air brake system that is used to adjust the brakes
B - between the push rod and S-cam on drum brakes
C - between the power screw and push rod on disc brakes
D - all of the above - ANSWER D - all of the above
What is the best way to test your vehicle's low air pressure warning signal?
A - pump the brakes while your vehicle is fully on
B - with the engine off, step on and off the brake pedal to lower the air pressure below
60 PSI
C - pump the brakes until the air pressure drops below 30 PSI
D - manually let the air out of your brakes and see if the signal comes on - ANSWER B
- with the engine off, step on and off the brake pedal to lower the air pressure below 60
PSI
Which of the following is NOT part of the braking process when driving a tractor-trailer
combination vehicle with an anti-lock braking system (ABS)?
A - you should drive faster so that you will be able to keep the trailer and tractor straight
B - brake the same way no matter what you're driving; a vehicle with ABS, a vehicle with
a trailer, or something else
C - when you slow down, you should monitor your tractor and trailer and ease off the
brakes to keep control
D - you should use only the braking necessary to stay safely in control - ANSWER A -
you should drive faster so that you will be able to keep the trailer and tractor straight
How can you tell if your vehicle is equipped with an anti-lock braking system (ABS)?
CORRECT 100%
An anti-lock braking system (ABS)
A - increases your normal braking capability
B - decreases your normal braking capability
C - activates when your wheels are about to lock up
D - shortens your stopping distance - ANSWER C - activates when your wheels are
about to lock up
Which of the following are true about a dual air brake system?
A - usually, one system operates the front axle and the other one operates the rear axle
B - one system is called the "primary" system and the other one is called the
"Secondary" system
C - it uses a single set of brake controls
D - all of the above are true - ANSWER D - all of the above are true
Which of the following is NOT part of the air brake system?
A - Radio signal system
B - Parking brake system
C - Service brake system
D - Emergency brake system - ANSWER A - Radio signal system
Which of the following will be true about your brake function if your anti-lock braking
system (ABS) fails?
A - it may cause problems with other mechanical systems and possibly pose a huge fire
risk
B - you will have no brake function and your truck will be out of control
C - it will slow your truck to a halt and force you to pull over
D - you will still have normal brake function and will just need to get the ABS repaired
soon - ANSWER D - you will still have normal brake function and will just need to get
the ABS repaired soon
At what measurement is the safety valve USUALLY set to open?
A - 150 PSI
B - 200 PSI
C - 250 PSI
D - 100 PSI - ANSWER A - 150 PSI
, Spring brakes are
A - made up of powerful springs that are held back by air pressure while you are driving
B - not going to take full effect until your PSI drops to a certain range, typically 20 to 30
PSI
C - brakes that come on automatically on a truck or tractor when the PSI drops too low
D - all of the above - ANSWER D - all of the above
The tractor protection valve
A - will close if you apply the parking brakes
B - provides the air supply for the brake system
C - will close automatically if the air supply drops to a certain level
D - does all of the above - ANSWER D - does all of the above
Slack adjusters are
A - part of the air brake system that is used to adjust the brakes
B - between the push rod and S-cam on drum brakes
C - between the power screw and push rod on disc brakes
D - all of the above - ANSWER D - all of the above
What is the best way to test your vehicle's low air pressure warning signal?
A - pump the brakes while your vehicle is fully on
B - with the engine off, step on and off the brake pedal to lower the air pressure below
60 PSI
C - pump the brakes until the air pressure drops below 30 PSI
D - manually let the air out of your brakes and see if the signal comes on - ANSWER B
- with the engine off, step on and off the brake pedal to lower the air pressure below 60
PSI
Which of the following is NOT part of the braking process when driving a tractor-trailer
combination vehicle with an anti-lock braking system (ABS)?
A - you should drive faster so that you will be able to keep the trailer and tractor straight
B - brake the same way no matter what you're driving; a vehicle with ABS, a vehicle with
a trailer, or something else
C - when you slow down, you should monitor your tractor and trailer and ease off the
brakes to keep control
D - you should use only the braking necessary to stay safely in control - ANSWER A -
you should drive faster so that you will be able to keep the trailer and tractor straight
How can you tell if your vehicle is equipped with an anti-lock braking system (ABS)?
