Air brake 2 Flashcards
The proper use of brakes when going down a long steep grade after selecting a proper gear is to brake =until your speed is about ____ below the posted speed and release your brake
5 mph
To check the free play of manual slack adjusters of S-cam brakes, you should park on
on Level ground chock the wheels and release the parking brakes
If you must make an emergency stop, you should brake so you
Can steer and keep your vehicle in a straight line
With air brake vehicles, the parking brake should be used
Whenever you leave your vehicle unattended
The braking system that applies and releases the brakes when the driver uses the brake pedal is the ____ brake system
Service
If your truck has a dual air brake system, and one of the systems is low on pressure
Either the front or rear brakes will not be fully functional
Why should you drain water from compressed air tanks?
Water can freeze in cold weather and cause brake failure
How should you check that your service brakes are working properly?
Park on level ground, wait until normal air pressure is reached, release the parking brake and move forward slowly at about 5 mph. Then apply the brakes firmly
Your brakes are fading when
You have to push harder on a brake pedal to control your speed on a downgrade
An air brake system is fully charged at what PSI?
125 PSI
What is a \”Wig Wag”\
A mechanical arm that signals low air pressure
Air brake takes more time than hydraulic braking because
Air brake take more time to flow through the lines than hydraulic fluid
It is accepted that too much heat caused by using your brakes too often can also cause
Brake to fade or fail
The safety valve discharges automatically at the pressure of
150 PSI
Modern air brakes combine three different systems. They are the service, the parking, and the _____ brake
Emergency
The air compressor stops pumping air at what PSI?
125 PSI
If you must make an emergency stop, you should brake so you
Can keep your vehicle in a straight line
The S - cam
Forces the brake shoes against the inside of the brake drum
The brake pedal in an air brake system
Controls the air pressure applied to the brakes
The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks fall below ___ PSI
60 PSI
Excessive heat caused by using your brakes too often can also cause
Brake to fade or fail
Excessive use of the service brakes results in overheating which can lead to
Expansion of the brake drum
If you do not have automatic tank drains, how often should you drain the oil and water from he bottom of the compressed air storage tanks?
At the end of each day of driving
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?
Bring your vehicle to a complete stop right away and safely park. Continue only after the system is fixed
When is it ok to leave your truck unattended without applying the parking brakes and choking the wheels?
Never
Which of these is NOT a proper time to apply the parking brakes?
If the brakes are very hot (e.g. coming down a steep hill)
A slack adjuster’s free play need to be adjusted if it is more than about ____ when you pull hard on it
1 inch
The application pressure gauge shoes hoe much air pressure you
Are applying to the brakes
What happens when your brake drums get very hot?
They expand
The braking power of the spring brakes
Depends on the service brakes being in adjustment
