Air brakes MOSTLY TESTED REVISION QUESTIONS AND ANSWERS
2024-2025
Study online at https://quizlet.com/_garag4
1. Oil & water usually collect in compressed air tanks. If you do NOT have an
automatic tank drain, when should you drain the air tanks: a. After every working
day.
b. After every four hours of service.
c. Once a week.
d. Every other week.
Correct Answer: After every working day.
2. Why drain water from the compressed air tanks?: Water can freeze in cold
weather and cause brake failure.
3. The air brakes system for a straight truck or bus should not leak at a rate of
more than ___ psi per minute with the engine off & the brakes released: 2
4. To make an emergency stop with air brakes, using the stab braking method,
you should:: Press on the brake pedal as hard as you can, release the brakes when
the wheels locked, put on the brakes again when the wheels start rolling.
5. You should know that your brakes are fading when:: You have to push harder
on the brake pedal to control your speed on a downgrade.
6. If the air compressor should develop a leak, what keeps the air in the
tanks?: The one way check valve
7. To check the brake slack on S-cam brakes you should park on: Park on level
ground, chock the wheels, and release the parking brakes
8. The application pressure gauge shows how much air pressure you:: When
you are applying to the brakes
9. The spring brakes used on the chambers in a straight truck will bring you
to a stop when air pressure drops below ___ psi: 20
10. The safety valve is set to automatically reduce pressure at ___ psi: 150
11. Your truck has a dual air system and one of the system loses its pressure,
what will happen: Either the front or back brake will not be fully operational.
12. If your truck or bus has dual parking control valves, you can use pressure
from a separate tank to:: Release the spring emergency/parking brakes to move
a short distance.
13. If your truck has a properly functioning dual air brake system and minimum
size air tanks. The air pressure should build from 85 to 100 within ____
seconds: 45
14. During normal driving, spring brakes are usually held back by:: air pressure
15. The air compressor stops pumping air at what psi: 125
16. The driver must be able to see a warning before pressure in the service air
tanks falls below ___ psi: 55 or 60
17. Excessive use of the service brakes results in overheating which can lead
to: Expansion of the brake drums
1/6
, Air brakes MOSTLY TESTED REVISION QUESTIONS AND ANSWERS
2024-2025
Study online at https://quizlet.com/_garag4
18. The most common type of foundation brake found on heavy vehicles is
the: S-cam drum brake
19. If you must make an emergency stop, brake so you:: Can steer and your
vehicle stays in a straight line.
20. The braking power of the spring brakes: Depends on the service brakes being
in adjustment
21. The air brakes lag distance at 55mph on dry pavement adds about ___
feet: 32 ft
22. Total stopping distance for air brakes is longer than that for hydraulic
brakes due to ___ distance: Brake lag
23. It is accepted that too much heat caused by using your brakes too often
can also cause:: Brake fade or failure
24. Repeatedly pressing and releasing (fanning) the brake pedal may result
in:: The loss of brake air pressure
25. The brake system that applies and releases the brakes when the driver
uses the brake pedal is the ________ brake system.: service
26. A slack adjuster's free play need to be adjusted if it is more than about ___
how many inches when you pull hard on it: 1 inch
27. An air brake system is fully charged at what psi?: 125
28. The brake pedal in an air brake system: Controls the air pressure applied to
put on the brakes
29. The S-cam: Forces the brake shoes against the inside of the brake drum
30. Under normal conditions in order to engage the parking brakes the driver
must first: Let the air out of the spring brakes.
31. Which of these is NOT a proper time to apply the parking brake: If your
brakes are very hot
32. If the spring brakes are on, when should you push the brake pedal: never
33. What is the first thing you should do when a low air pressure warning
comes on: Stop & safely park as soon as possible
34. The parking or emergency brake on a heavy vehicle can only be held in
position by something that cannot leak away, like: Spring pressure
35. Air braking takes more time than hydraulic braking because air brakes:: -
Takes more time to flow through the lines than hydraulic fluid
36. When you apply the brakes, the brake shoes/linings are pressed against
the: brake drum
37. If air pressure is NOT build up fast enough within the correct amount of
time: You air pressure may drop too low during driving
2/6
2024-2025
Study online at https://quizlet.com/_garag4
1. Oil & water usually collect in compressed air tanks. If you do NOT have an
automatic tank drain, when should you drain the air tanks: a. After every working
day.
b. After every four hours of service.
c. Once a week.
d. Every other week.
Correct Answer: After every working day.
2. Why drain water from the compressed air tanks?: Water can freeze in cold
weather and cause brake failure.
3. The air brakes system for a straight truck or bus should not leak at a rate of
more than ___ psi per minute with the engine off & the brakes released: 2
4. To make an emergency stop with air brakes, using the stab braking method,
you should:: Press on the brake pedal as hard as you can, release the brakes when
the wheels locked, put on the brakes again when the wheels start rolling.
5. You should know that your brakes are fading when:: You have to push harder
on the brake pedal to control your speed on a downgrade.
6. If the air compressor should develop a leak, what keeps the air in the
tanks?: The one way check valve
7. To check the brake slack on S-cam brakes you should park on: Park on level
ground, chock the wheels, and release the parking brakes
8. The application pressure gauge shows how much air pressure you:: When
you are applying to the brakes
9. The spring brakes used on the chambers in a straight truck will bring you
to a stop when air pressure drops below ___ psi: 20
10. The safety valve is set to automatically reduce pressure at ___ psi: 150
11. Your truck has a dual air system and one of the system loses its pressure,
what will happen: Either the front or back brake will not be fully operational.
12. If your truck or bus has dual parking control valves, you can use pressure
from a separate tank to:: Release the spring emergency/parking brakes to move
a short distance.
13. If your truck has a properly functioning dual air brake system and minimum
size air tanks. The air pressure should build from 85 to 100 within ____
seconds: 45
14. During normal driving, spring brakes are usually held back by:: air pressure
15. The air compressor stops pumping air at what psi: 125
16. The driver must be able to see a warning before pressure in the service air
tanks falls below ___ psi: 55 or 60
17. Excessive use of the service brakes results in overheating which can lead
to: Expansion of the brake drums
1/6
, Air brakes MOSTLY TESTED REVISION QUESTIONS AND ANSWERS
2024-2025
Study online at https://quizlet.com/_garag4
18. The most common type of foundation brake found on heavy vehicles is
the: S-cam drum brake
19. If you must make an emergency stop, brake so you:: Can steer and your
vehicle stays in a straight line.
20. The braking power of the spring brakes: Depends on the service brakes being
in adjustment
21. The air brakes lag distance at 55mph on dry pavement adds about ___
feet: 32 ft
22. Total stopping distance for air brakes is longer than that for hydraulic
brakes due to ___ distance: Brake lag
23. It is accepted that too much heat caused by using your brakes too often
can also cause:: Brake fade or failure
24. Repeatedly pressing and releasing (fanning) the brake pedal may result
in:: The loss of brake air pressure
25. The brake system that applies and releases the brakes when the driver
uses the brake pedal is the ________ brake system.: service
26. A slack adjuster's free play need to be adjusted if it is more than about ___
how many inches when you pull hard on it: 1 inch
27. An air brake system is fully charged at what psi?: 125
28. The brake pedal in an air brake system: Controls the air pressure applied to
put on the brakes
29. The S-cam: Forces the brake shoes against the inside of the brake drum
30. Under normal conditions in order to engage the parking brakes the driver
must first: Let the air out of the spring brakes.
31. Which of these is NOT a proper time to apply the parking brake: If your
brakes are very hot
32. If the spring brakes are on, when should you push the brake pedal: never
33. What is the first thing you should do when a low air pressure warning
comes on: Stop & safely park as soon as possible
34. The parking or emergency brake on a heavy vehicle can only be held in
position by something that cannot leak away, like: Spring pressure
35. Air braking takes more time than hydraulic braking because air brakes:: -
Takes more time to flow through the lines than hydraulic fluid
36. When you apply the brakes, the brake shoes/linings are pressed against
the: brake drum
37. If air pressure is NOT build up fast enough within the correct amount of
time: You air pressure may drop too low during driving
2/6
