100%
To test air service brakes you should: - ANSWER Brake firmly while slowly moving
forward
The driver must be able to see a low air pressure warning which comes on before
pressure in the service air tanks falls below ____ psi - ANSWER 60
If your vehicle has an alcohol evaporator, every day during cold weather you should: -
ANSWER Check and fill the alcohol level
All air brakes equipped vehicles have: - ANSWER A supply pressure gauge
The most common type of foundation brake found on heavy vehicles is the: - ANSWER
S-cam drum
Modern air brakes combine three different systems. They are the service, the parking,
and the ___ brakes. - ANSWER Emergency
To check the free play of manual slack adjusters of s-cam brakes, you should park on: -
ANSWER Level ground, chock the wheels and release parking breaks
Why should you drain water from compressed air tanks? - ANSWER Water can freeze
in cold weather and cause brake failure
The spring brakes used on the chambers in a straight truck will bring you to a stop when
air pressure drops below____ psi - ANSWER 20
With air brake vehicles, the parking brake should be used: - ANSWER Whenever you
leave the vehicle unattended
The safety valve is set automatically when pressure is - ANSWER 150
Repeatedly partially increasing and pressing the brake pedal may result in: - ANSWER
A loss of air brake pressure
If your truck has dual air brake system, and one of the systems loses its pressure, what
will happen? - ANSWER Either the front or rear brakes will not be fully functional
If you must make an emergency stop, you should brake so you: - ANSWER Can steer
and so your vehicle stays in a straight line
, The air loss rate for a straight truck or bus with the engine off and the brakes on should
not be more than: - ANSWER 3 psi in one minute
You brakes are fading when: - ANSWER You have to push harder on a brake pedal to
control your speed on a downgrade
Which one of these is NOT a proper time to apply the parking brakes? - ANSWER If
the brakes are very hot
The braking power of the spring brakes: - ANSWER Depends on the service brakes
being in adjustment
Your truck or bus has a dual air brake system. If a low pressure warning comes on for
only one system, what should you do? - ANSWER Bring your vehicle to a complete
stop right away and safely park. Continue only after the system is fixed
A slack adjusters free play needs to be adjusted if it is more than about _____ when you
pull hard on it. - ANSWER 1 inch
The air brake lag distance at 55 mph on dry pavement adds about _____ feet -
ANSWER 32
Excessive use of the service brake results in overheating which can lead to: - ANSWER
Expansion of the brake drums
When is it OK to leave your truck unattended without applying the parking brakes and
choking the wheels? - ANSWER never
The use of brakes on a long and steep downgrade under normal conditions is only a
supplement to: - ANSWER the breaking effect of the engine
The parking or emergency brake on a heavy vehicle can only be held in position by
something that cannot leak away, like: - ANSWER Spring pressure
Is it accepted that too much heat caused by using your brakes too often can also cause:
- ANSWER Brake to fade or fail
The most important thing to do when a low air pressure warning comes on is: -
ANSWER Stop and safely park as soon as possible
With air brake vehicles, the park brakes should be used: - ANSWER Any time when
vehicle is parked
If the spring brakes are on, when should you push on the brake pedal? - ANSWER
Never