Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
12 Cards in this Set
- Front
- Back
|
The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like:
-Spring pressure -Air pressure -Hydraulic pressure |
Modern airbrakes are three different systems combined together they are: service, parking, and the _______ brakes
-emergency -food -s-cam |
|
|
The air supply pressure gauge shows how much pressure
-is in the air tanks -you have used in this trip -is going to the brake chambers |
The parking or emergency brakes of trucks and buses can legally be held on by ________ pressure
-spring -fluid -air |
|
|
All air brake equipped vehicles have:
-an air supply pressure gauge -an air use gauge -a backup hydraulic system |
The stop light switch:
-turns on the brake lights to warn the driver behind you -tells you when you need to use your emergency brakes -tells you when the air brake system is low on air pressure |
|
|
When you apply the brakes the brake shoe lining are pressed against the
-brake drum -slack adjuster -s-cam |
If your vehicle has an alcohol evaporator it is there to
-rid the wet tank of alcohol the compresses and sits at the bottom -eliminate the need for daily tank draining -reduce the risk of ice in air brake valves in cold weather |
|
|
Why should you drain water from compressed air tanks
-the volume point reduces braking power -water can freeze in cold weather and cause brake failure -water cools the compressor too much |
If air pressure does not build up fast enough within the correct amount of time
-you should be ready to use your parking brake to help stop -the alcohol container may be low -the air pressure may drop too low during driving
|
|
|
The driver must be able to see a warning before air pressure in the service air tanks falls below _______ PSI
-20 -50 -100 |
How should you check that your service brakes are working properly:
-park on a slight incline, drain off air pressure, set the parking brakes and check for movement -park on level ground, chock the wheels, engage the parking brake, shut engine off -wait for normal air pressure, release the parking brake, remove the truck forward slowly, apply brake firmly using brake pedal |
|
|
To check the brake slack on s-cam brakes you should park on
-level ground and apply parking brake -level ground, chock the wheel, release parking brake -A slight grade, release the parking brakes, and apply the service brakes, watching for vehicle movement |
The air brake system for a straight truck or bus should not leak at a rate of more than ______ psi per minute with the engine off and the brakes released
-1 -3 -2 |
|
|
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:
-1 psi in one minute -2 psi in 45 seconds -3 psi in one minute |
The safety valve is set to automatically reduce pressure at ______ psi
-50 -100 -150 |
|
|
Air braking takes more time than hydraulic braking because air:
-brakes use different brake drums -takes more time to flow through the lines than hydraulic fluid -brakes require heavier return springs |
Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to _____ distance
-Brake lag -reaction -effective braking |
|
|
With air brake vehicles, the parking brakes should be used:
-whenever you leave the vehicle unattended -as little as possible -only during pre-and post-trip inspections |
A truck with air brakes going 55 mph would require a stopping distance of
-less than 100 feet -100-300 feet -more than 300 feet |
|
|
The air brake lag distance at 55 mph on dry pavement adds about _______ feet to your stopping distance
-12 -32 -52 |
The use of air brakes on a downgrade is only a supplement to the:
-use of the spring brakes -use of the front brake limiting valve -braking effect of the engine |
|
|
Excessive heat in the brakes can cause the
-modulating control to wear out -brake lines to plug -brakes to fade or fail |
You are on a steep downgrade and have reached your "safe" speed of 40 mph. You would apply the service brakes until your speed drops to ____ mph
-25 -30 -35 |
