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Air Brake Questions: Day 1 Module 2

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1How is heat dissipated that is generated by the brakes?9If the brakes do not seem to be holding even though
sufficient air pressure is present, you should:
a)Dissipated by the speed of the vehicle.
b)Absorbed by the brake drums and dissipated into the a)Report the condition at the end of the trip.
atmosphere.b)Travel at reduced speed.
c)Dissipated by the air temperature.c)Stop, check brakes and adjust if required.
d)Supply air to increase braking effort on a steep grade
2If one set of brake shoes is poorly adjusted, what effect could  if main reservoir air is lost.
it have on the remaining sets of brake shoes in the system?e)Supply air to temporarily release the parking brake 
if main reservoir air is lost.
a)The brakes would automatically equalize themselves.f)Supply air to stop the vehicle if main reservoir air is lost.
b)They would increase their share of the braking, possibly
causing overheating.10What is the main cause of brake fade at higher
c)There would be no noticeable effect on the remaining sets temperatures?
of brake shoes.
a)The air pressure becomes hot.
3If 40 PSI is exerted against a diaphragm of 30 square inches b)The brake linings expand away from the drums.
in area, what is the total force that could be exerted?c)The brake drums expand away from the linings.
a)1200 lbs of force11What is meant by braking distance?
b)1200 PSI
c)1200 kpaa)The actual distance the vehicle travels after the brake
d)1200 kmhis applied, until the vehicle stops.
b)The actual distance the vehicle travels from the moment
4If the weight of a vehicle is doubled, how many times must the a hazard is recognized to the time the vehicle stops.
stopping power be increased to stop in the same distance?c)The actual distance the air travels through a properly
maintained air-brake system.
a)Six times.
b)Eight times.12If a small leak develops in a brake chamber, what type of
c)Two times.valve will continue to hold the same application of
d)Four times.the chamber?
5Signs posted in advance to a down grade, instructing drivers a)Poppet.
of trucks to stop and inspect their brakes, are?b)Graduating
c)Balancing.
a)Regulatory signs.
b)Warning signs.13In which direction should the adjusting nut be turned to
c)Advisory signs.tighten the brakes?
6If slack adjuster travel is checked while someone makes aa)Clockwise.
brake application, travel should not exceed:b)Same direction as the S-Cam shaft.
c)Make the S-Cam shaft rotate in the same direction as an
a)2 inchesair application.
b)   3/4 inches.
c)2 1/2 inches.14On a long steep downgrade, the best method of using
d)1 3/4 inches.brakes is:
7What is the final factor that will determine if the vehiclea)Hard on, then off to allow brakes to cool, then hard
will move?on again.
b)Snubbing as required.
a)The amount of power.c)Continuous application of 25 PSI.
b)The amount of friction.d)Steady brake application of 10 PSI or less.
c)The amount of traction.e)Do not use it.
8To stop a vehicle the energy of motion is turned into:15What is the purpose of a quick release valve?
a)Heat in the brake lining and drums.a)To prevent brake lag.
b)Moisture in the reservoirs.b)To allow the brakes to release quickly.
c)Traction.c)To allow air to escape quickly from the treadle valve.

16What is the purpose of a relay valve?24How can spring brakes be released without the use of
air pressure?
a)To reduce application pressure to the front
brake chambers.a)Disconnect the slack adjuster and push rods.
b)To relay reservoir air directly to the treadle valve.b)Release the brakes by turning the adjuster of the
c)To provide quicker application pressure to the slack adjuster.
brake chambers, reducing lag time.c)Caging the (spring) brakes.
17Compounding of the brakes will result in some vehicles when?25What is meant by the term "friction"?
a)A full brake application is made when the spring parking a)The factor which stops the vehicle.
brakes are released.b)The factor which moves the vehicle.
b)A full brake application is made when the spring parkingc)The force which resists movement between two surfaces
brakes are applied.in contact with each other.
c)A full brake application is made when the hand valve
is applied.26A third tank spring release will allow a driver to:
18An automatic front wheel limiting valve is over-ridden when a)Move a disabled vehicle to safety.
application exceeds:b)Slowly drive a disabled vehicle to the nearest repair
depot.
a)40 PSI.c)Operate in the state of California.
b)60 PSI.
c)80 PSI.27Spring brakes are most useful as:
19What is the most common cause of loss of effective a)A reserve brake if the service brakes fail.
braking on air equipped vehicles?b)A parking brake.
c)An emergency stopping device.
a)Brakes are out of adjustment.
b)Over heated brake drums.28If the speed and the weight of a vehicle is doubled, how
c)Loss of air pressure.many times must the braking force be increased to be able
to stop in the same distance.
20If the brakes are out of adjustment, is the force of the spring
brakes when applied:a)2 times.
b)4 times.
a)The same.c)6 times.
b)Greater.d)8 times.
c)Less.
29A good way to test the holding power of a spring brake is to:
21On a full brake application in a tractor and semi-trailer with
maximum air pressure, air loss should not exceed:a)Apply the spring brake while the vehicle is moving.
b)Allow the spring brake to hold a vehicle on a grade.
a)4 PSI per minute.c)Tug test in low gear, spring brake applied.
b)2 PSI per minute.
c)6 PSI per minute.30When checking slack adjuster push rod travel by hand or
d)8 PSI per minute.pry bar, travel should not exceed:
22Braking systems that have automatic slack adjusters:a)2 inches.
b)2 1/2 inches.
a)Do not need to be checked for adjustment.c)1/2 to 3/4 inches.
b)Must be checked regularly to ensure correct adjustment is
maintained.31When should a driver use the manual front wheel
c)Must be checked occasionally for correct adjustment. limiting valve?
23A quick release valve is sometimes used with spring a)When necessary on slippery roads to reduce front brake
brakes to:application by 50%.
b)When necessary on slippery roads to reduce front brake
a)Allow automatic application.application by 25%.
b)Allow faster application.c)When necessary on slippery roads to cut-out front
c)Allow faster release.wheel brakes.

32The stopping distance of a vehicle is most affected by:39Proper brake adjustment on "S" cam brakes is determined
by:
a)The condition of the brakes.
b)The condition of the highway.a)The size of the brake chambers.
c)The speed of the vehicle.b)The brake chamber push rod travel.
c)The length of the slack adjusters.
33Unless a spring brake system has an anti-compounding
device, the spring brakes should be released before 40A pressure protection valve is used to:
making a full brake application test, because:
a)Cut down braking forces under slippery conditions.
a)The brakes will apply too quickly.b)Protect the reservoir from over pressuring.
b)The compounding force may damage the slack adjusters.c)Prevent failure of air accessories from totally depleting
c)You will not get a true reading.the system.
34The speed at which a vehicle should travel on a 41"Brake lag" is approximately 4/10th of a second in a well
downgrade is best determined by:maintained brake system. What is meant by the term
Brake lag?
a)The condition of the road.
b)The necessity to be able to make an emergency stop.a)The time it takes from the moment a hazard is
c)The length and percentage of the grade.recognized to the time the brake is applied.
d)The condition of the brake lining.b)The actual time the vehicle takes to stop after the brake
is applied.
35What are the main components of a simple air brake system?c)The time the air pressure takes to fully apply the brakes
after the treadle is depressed.
a)Air lines, reservoir, brake pedal, foundation brakes, spring-
lines.42The final factor which will determine if a vehicle will stop is:
b)Compressor, air lines, brake pedal.
c)Compressor, air lines, reservoir, brake pedal, foundationa)Reservoir air pressure.
brakes.b)Brake adjustment.
d)Air lines, reservoir, foundation brakes, spring-line.c)Traction.
36Why should you avoid compounding the air brakes?43Brake adjustment is best checked by:
a)You can cause damage to the slack adjusters a)Watching the slack adjuster as a full brake application
and s-cams.is made.
b)You can cause damage to the brake chamber mountingb)Pulling the slack adjuster with a pry bar.
bolts, brake shoe rollers, shoes and brake drums.c)Rolling ahead slowly and making a brake application.
c)You will risk damage by putting too much force on the
brake components.44What is a safety actuator parking brake?
d)All of the above.
a)An automatic park brake.
37Water in the reservoir is harmful to the air system because:b)A spring brake lock.
c)A caging device.
a)It carries dirt to the valves.d)An air operated parking brake used in some buses.
b)It corrodes the air lines.
c)It freezes in cold weather.45What is a long-stroke brake chamber design?
d)It cuts down reservoir pressure.
a)A brake chamber used on front brake chambers.
38How is heat dissipated that is generated by the brakes?b)Allows a "Type 30" brake to stroke 3.
c)Used on long trailers only.
a)Dissipated by the speed of the vehicle.d)Used on "A" and "B" trailers only.
b)Absorbed by the brake drums and dissipated into
the atmosphere.46What does the term "bottoming out" mean with air brakes?
c)Dissipated by the air temperature.
a)The brake chamber hits the truck frame when applied.
b)The foot valve hits the floor when applied.
c)The push rod travels to the base of the chamber.
d)This occurs due to low air pressure.

47At what RPM is the engine set when performing the 56When the vehicle is in motion, spring brakes are held
air pre-trip inspection?released by:
a)Low idle.a)A locking device on the spring brake piston.
b)1000 to 1200 RPM.b)The diaphragm return spring.
c)1700 RPM.c)System air pressure.
d)Maximum RPM.
57CMVSS 121 requires that the low pressure warning
48How are service brakes tested to ensure they are working?signal must be:
a)Drive slowly in traffic and try them.a)A red light.
b)On back roads away from other cars.b)Both audible and visual.
c)Roll forward slightly and apply the brakes.c)A buzzer.
d)Pump the brake pedal and read the gauge.
58When a safety valve blows off, it indicates that there
49How are spring type parking brakes held in the released is a problem in the:
position?
a)Compressor exhaust valves.
a)By spring pressure.b)Governor or unloading system
b)By application pressure.c)Low pressure warning circuit.
c)By air pressure.
59Wedge brakes are equipped with:
50A foot valve is a valve that:
a)One brake chamber only.
a)Will automatically adjust to braking requirements.b)one or two brake chambers.
b)Needs reservoir pressure to control it to within 10 PSI.c)Two brake chambers of different sizes.
c)Once applied, it continuously maintains applied pressure.
60With the brakes fully applied, the angle between the
51During the braking of a vehicle the energy of motion is slack adjuster arm and the push rod should:
converted into:
a)Always be greater than 45 degrees.
a)Heat energy.b)Be between 75 and 105 degrees.
b)Static energyc)Never less than 90 degrees.
c)Kinetic energy.
61Before checking and adjusting brakes, the :
52One of the final items of the pre-trip inspection is to:
a)System pressure should be reduced to 621 KPA (90 PSI)
a)Build the systems pressure to maximum and test the b)Wheels should be blocked.
spring brake.c)The spring brakes should be applied.
b)Move the vehicle ahead slowly and test the service
brake response.62The slack adjuster provides a means for:
c)Fan the brakes until the spring brakes apply.
a)Centering the diaphragm in the brake chamber housing.
53An application air gauge indicates:b)preventing roll over of the brake cam.
c)Reducing the clearance between the lining and the drum.
a)The pressure in the primary system.
b)The approximate pressure in the brake chamber.63What are "foundation brakes"?
c)The cut-in pressure of the governor.
a)The mechanical parts of the brake assembly.
54If the brake pedal of an air braked vehicle is pumped, it will:b)Brakes on "Super B" trains only.
c)Brakes used on tour buses only.
a)Assist in cooling the brake drums.d)Moves used in hydraulic systems only.
b)Make up for poorly adjusted brakes.
c)Lower the reservoir pressure.64The first reservoir after the compressor is called the:
55On brake assemblies with dust covers a visual check a)Service reservoir.
should be made of the:b)Wet tank.
c)Primary tank.
a)"S" cam condition.
b)Brake shoe anchors.
c)Brake lining thickness and condition.

65When approaching a stop sign with a loaded truck,
the brakes should be applied:
a)The same as a car.
b)Close to the stop sign with a hard application.
c)Early, to spread out the braking load.
66The limit of the retarding force that is generated by the
brakes is controlled by:
a)Tire condition and inflation.
b)Axle weight.
c)Traction.
67What is compressed air?
a)Air inside the empty reservoirs.
b)Air that is squeezed into a smaller space than it would
normally occupy.
c)Atmospheric pressure.
d)Air inside of a deflated tire.
68Why does the "feel" of an air-operated foot valve differ
from a hydraulic brake pedal?
a)Because it is using air fluid.
b)It is an illusion created by the size of the vehicle.
c)Air treadles are spring loaded.
d)Air treadles are not mechanical at all.
69A basic air brake system capable of stopping a vehicle
has __________ mair components.
a)Two.
b)Three
c)Four.
d)Five.
70Heat that is generated by braking is dissipated through the:
a)Metal brake drums.
b)Brake chambers.
c)Brake shoes.
d)Wheel bearings.

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