Air Brakes Flashcards
What are the three types of brake systems used in a commercial vehicle air brake system? A. Hand, parking, emergency B. Service, parking, emergency C. Anti-lock, service, emergency D. Service, hand, emergency
B. Service brake, parking brake, emergency brake
What type of air do air brakes use? A. Uncompressed air B. Warm air C. Compressed air D. Heated air
C. Compressed Air
What is the name of the device that pumps air into the air storage tanks? A. Governor B. Evaporator C. Safety valve D. Air compressor
D. Air compressor
What is the alcohol evaporator s primary purpose?
A. Remove water and oil from brake system
B. Remove alcohol from brake system
C. Put alcohol into the air system
D. Heat the air tank
C. To put alcohol into the air system
What psi level is the safety relief valve set to open at? A. 150 psi B. 125 psi C. 60 psi D. 100 psi
A. 150 psi
What is the most common type of foundation brake? A. Wedge brake B. S-cam drum brake C. Disc brake D. Anti-lock brake
B. S-Cam drum brake
Which if the following statements is true?
A. Front wheel braking is good under all conditions
B. front wheel braking will cause skids in ice
C. You should put a front brake limiting valve on slippery position in adverse conditions
D. Front wheel braking is ineffective in slippery conditions
A. Front wheel braking is good under all conditions
At what air pressure must the low air pressure warning signal come on? A. 150 psi B. 50 psi C. 45 psi D. 60 psi
D. 60 psi
Which of the following is true regarding spring brakes?
A. Spring brakes will come on at 150 psi
B. Spring brakes are held by mechanical force
C. Spring brakes use air pressure to stop
D. Spring brakes will not function if system loses air
B. Spring brakes are held by mechanical force
What indicates how much pressure you have in your air tanks? A. Application pressure gauge B. Low air pressure warning signal C. Ammeter D. Supply pressure gauge
D. Supply pressure gauge
What is the primary purpose of a front brake limiting valve?
A. Improved stopping a ability
B. Cuts air pressure to front brakes by 1/2
C. Detects road conditions and switches as necessary
D. Increases stopping ability of rear brakes
B. Cuts the air pressure of the front brakes by half
Which of the following will affect the stopping power of spring brakes? A. Road conditions B. Proper adjustment C. Modulating control valve position D. All of the above
D. All of the above
Where are foundation brakes used? A. Emergency situations B. Front axles only C. All wheels D. When parking
C. All wheels
Which of the following parts of the air brake system should be checked during the pre-trip walk around inspection?
A. Slack adjusters on S-cam brakes
B. Air hoses connected to the brake chambers
C. Brake discs or drums
D. All of the above
D. All of the above
During inspection, if a slack adjuster moves less than an inch where the push rod attaches, which of the following statements is true? A. Fail roadside inspection B. Needs adjustment C. Appropriate slack D. Vehicle will be hard to stop
C. Appropriate slack
When testing the air leakage rate what is an acceptable air loss rate? A. Less an 2 psi single 3 psi combo B. Less than 3 psi both single/combo C. Less than 3 psi single 2 psi combo D. Less than 2 psi both
A. Less than 2 psi single 3 psi combo
Which of the following is not a step in testing spring brakes coming on automatically? A. Release parking brake B. Pump brake pedal repeatedly C. Shut engine off D. Pull out parking brake control knob
D. Pull out parking brake control knob
If you use controlled braking, which of the following is an acceptable procedure?
A. Need to turn then keep brakes applied
B. Apply brakes all the way to lock wheels
C. Release brakes if need to make large steering adjustment
D. If wheels sliding, press brake harder
C. Release brakes if need to make large steering adjustment
What should you do if the low air pressure light comes on?
A. Stop and safely park your vehicle ASAP
B. Drive to nearest service station
C. Use stab braking
D. No immediate action
A. Stop and park safely ASAP
What is the proper technique to use when braking on downgrades?
A. Stab braking
B. Controlled braking
C. Apply brakes enough to slow 5 mph below safe speed
D. Repeatedly pump brakes
C. Apply brakes enough to slow 5 mph below safe speed
If your vehicle does not have automatic air tank drains, how often should you drain the tanks? A. Once a week B. Every 1,000 miles of travel C. At the end of each working day D. Twice a week
C. At the end of each working day
When is it acceptable to NOT use parking brakes if you leave vehicle unattended? A. Flat road surface B. Gone a shirt time C. Wheels turned at harsh angle D. Never
D. Never
When should parking brakes NOT be used? A. Brakes are wet in freezing weather B. Brakes are hot C. Checking that doting brakes can come on automatically D. All of the above
D. All of the above
Which device is designed to protect the air tank and system from too much air pressure? A. Drain valve B. Safety valve C. Governor D. Evaporator
B. Safety valve
What should you do before driving vehicle with dual air system? A. Both systems 85 psi B. Primary 125 psi secondary 100 psi C. Primary 100 psi secondary 85 psi D. Both systems 100 psi
D. Both systems 100 psi
If you press and release the brake pedal repeatedly what will happen?
A. Let out air faster than compressor can replace it
B. Stop straighter and faster
C. Safely control speed around curve
D. Cool brakes rapidly
A. Let air out faster than air compressor can replace it
What is another term for a brake pedal? A. Brake shoe B. Treadle valve C. S-cam D. Wedge brake
B. Treadle valve
What device controls when air compressor will pump air into the storage tanks? A. Evaporator B. Governor C. Safety valve D. Air tank drains
B. Governor
Which device helps reduce risk of ice in air brake systems? A. Air compressor governor B. Air tank drain C. Safety valve D. Alcohol evaporator
D. Alcohol evaporator
Which device allows you to remove oil and water from their brake systems? A. Air tank drain B. Safety valve C. Alcohol evaporator D. Treadle valve
A. Air tank drain
What does it mean when the safety valve open and releases air?
A. Pressure has exceeded 150 psi
B. System is fully charged
C. Something is wrong and a mechanic needs to check it
D. Both A and C
D. Both A and C
What should the air pressure loss be in a single vehicle with a fully charged system? A. Less than 2 psi B. Less than 3 psi C. Less than 4 psi D. Less than 5 psi
A. Less than 2 psi
In a combo vehicle, what should the air pressure loss be with a fully charged air system? A. Less than 2 psi B. Less than 3 psi C. Less than 4 psi D. Less than 5 psi
B. Less than 3 psi
Where is compressed air stored? A. Air compressor B. Pressure gauge C. Main reservoirs D. Service and emergency air lines
C. Main reservoirs
Which of the following devices indicates how much air pressure you are applying to your brakes? A. Application pressure gauge B. Low pressure warning signal C. Governor D. Supply pressure gauge
A. Application pressure gauge
Which of the following devices can be used as the low pressure warning signal? A. Buzzer B. Red warning light C. Mechanical arm D. Any of the above
D. Any of the above
What is a wig wag?
A. Device that cuts the normal air pressure to front wheels by half
B. Mechanical arm that comes into view when the air pressure falls below 60 psi
C. Another name for a brake pedal
D. Level used to apply spring brakes gradually
B. Mechanical arm that comes into view when air pressure falls below 60 psi
What is a modulating control valve?
A. Device that controls when air compressor will pump air into the air storage tanks
B. Device that cuts normal air pressure to front brakes by half
C. Valve used to drain oil and water from air storage tanks
D. Lever used to apply spring brakes gradually
D. Lever used to apply spring brakes gradually
What does the air compressor governor control?
A. When the air is released from the tank
B. When air pressure is cut to the front brakes
C. When air compressor pumps air into storage tanks
D. When water and oil are expelled from storage tanks
C. When air compressor pumps air into storage tanks
Which of the following steps should you use to check the slack adjusters on S-cam brakes?
A. Move more than an inch
B. Parking brake on, pull slack adjuster
C. Use gloves and pull hard on slack adjuster
D. Pull slack adjusters after draining air
C. Use gloves and pull hard slack adjusters
What is the typical pressure of a fully charged air brake system? A. 85 psi B. 150 psi C. 100 psi D. 125 psi
D. 125 psi
What is the proper way to test the air leakage rate?
A. Turn off engine and release parking brake
B. Fully charge air system and leave engine running
C. Leave engine running and release parking brake
D. Depress brake pedal and monitor the air pressure gauge
A. Turn off engine and release parking brake
What is stab braking?
A. Applying brakes as hard as possible w/out locking wheels
B. Using parking brake to slow vehicle I’m emergency
C. Applying brakes until wheels lock up, release, then reapply when moving again
D. Apply constant light pressure on brakes
C. Applying brakes until wheels lock up, release, reapply when starting to roll
Why do air brakes take longer than hydraulic ones?
A. Driver has increased reaction time
B. Takes longer for the air to flow through the lines
C. Air compressor adds a delay
D. All of the above
B. Takes longer for the air to flow through the lines
What will happen if your air compressor stops? A. Immediate loss of brakes B. Brakes lock up C. Still have air pressure left in tanks D. Brakes not affected
C. Still have air pressure in tanks
How should you check your air compressor governor “cut in”/”cut out” pressures?
A. Run engine at fast idle
B. Step on an off brake for reduced tank pressure
C. Monitor air pressure gauge
D. All of the above
D. All of the above
How fast should air pressure build in dual air system? A. 50-90 psi in 3 min B. 85-100 psi in 45 sec C. 70-125 psi in 60 sec D. 100-150 psi in 45 sec
B. 85-100 psi in 45 sec
What are typical air compressor governor cut-in and cut-out pressures? A. Cut-in: 100 psi; cut-out: 125 psi B. Cut-in: 60 psi; cut-out: 125 psi C. Cut-in: 100 psi; cut-out: 150 psi D. Cut-in: 90 psi; cut-out: 125 psi
C. Cut-in: 100 psi; cut-out: 125 psi
What device will keep air in the tanks if the air compressor develops a leak? A. Tractor protection valve B. One way check valve C. Safety valve D. Treadle valve
B. One way check valve
