Heavy Duty Truck Systems - Chapter 31, Chapter 8, Chapter 28, Chapter 7 || with 100% Verified Solutions.
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Heavy Duty Truck Systems - Chapter 31, Chapter 8,
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Heavy Duty Truck Systems - Chapter 31, Chapter 8,
Which of the following is the best practice when instructed to block the wheels on a tractor/trailer combination? correct answers Place a pair of wedged wheel chocks on one tractor drive axle and one trailer axle wheel.
What is the required amount of slack adjuster free travel on a properly adju...
Heavy Duty Truck Systems - Chapter 31, Chapter 8,
Chapter 28, Chapter 7 || with 100% Verified Solutions.
Which of the following is the best practice when instructed to block the wheels on a
tractor/trailer combination? correct answers Place a pair of wedged wheel chocks on one tractor
drive axle and one trailer axle wheel.
What is the required amount of slack adjuster free travel on a properly adjusted, manual S-cam
brake? correct answers 3/8 to 5/8 inch
Which of the following foundation brake components are lubricated with chassis grease, either
for component life or as part of a lube job? correct answers S-cam bushings
A 161/2 inch brake drum specified to have a machine limit of 0.090 inch over and a maximum
dimension of 0.120 inch over is measured at 0.098 inch over at a brake overhaul. Technician A
says that the drum can be turned on a drum lathe, providing that the maximum dimension of
0.120 inch is observed. Technician B says that the drum can be legally returned to service
without being turned. Who is correct? correct answers Technician B only
A tandem axle trailer equipped with S-cam brakes has all four slack adjusters originally set with
a 6-inch dimension from the clevis pin to the camshaft. One slack adjuster is replaced, and
because of a different hole arrangement in the new slack adjuster, it is set at 61/2 inches. Which
of the following is more likely to result? correct answers One of the four wheels will lock up
ahead of the others under severe braking
When adjusting a manual slack adjuster on an S-cam foundation brake, Technician A says that
the lock collar should be retracted and the adjusting nut always rotated clockwise to decrease
free travel. Technician B says that free travel can be reduced only when the adjusting nut is
rotated counterclockwise. Who is correct? correct answers Neither A nor B
A set of brake linings has become glazed because of oil saturation by a failed wheel seal.
Technician A says that pressure washing the foundation brake components should be sufficient
to remove the effects of the oil saturation. Technician B says that the best practice is to replace
the brake linings on both wheels on the affected axle. Who is correct? correct answers
Technician B only
When adjusting S-cam brakes on a trailer equipped with manual slack adjusters, which of the
following must be true? correct answers The trailer parking brakes must be released
An original equipment 45-degree elbow on a line exiting a relay valve supplying a service
chamber is replaced by a 90-degree elbow. Technician A says that this should have no effect on
brake performance because it is the service application pressure that determines braking force.
Technician B says that the use of the 90-degree elbow increases flow restriction and can affect
pneumatic timing. Who is correct? correct answers Technician B only
, Technician A says that the service diaphragm in a spring brake can be safely changed, providing
that the spring brake is properly caged with a cage bolt before removing it. Technician B says
that it is no longer possible to change the hold-off diaphragms in most spring brake assemblies
because the band clamp cannot be unbolted. Who is correct? correct answers Technician B only
What is the main function of a hold-off diaphragm? correct answers It prevents spring break
force from acting on the pushrod
When an S-cam foundation brake slack adjuster is in the fully applied position, ideally the slack
adjuster-to-pushrod angle should be: correct answers exactly 90 degrees
A tri-axle trailer is equipped with five S-cam slack adjusters correctly set at an effective length of
6 inches and one incorrectly installed at 51/2 inches. How much less brake torque will be applied
at the brake with the incorrectly set slack adjuster when the service application pressure is 100
psi on a 30-square-inch chamber? correct answers 1,500 lb-in
A leaking axle seal has saturated the brake shoe linings and caused them to glaze. Technician A
says that the shoes should be immersed in solvent before being returned to service. Technician B
says that if the brake shoes on both sides of the axle are not replaced, brake torque balance could
be affected. Who is correct? correct answers Technician B only
Technician A says that it is good practice to machine a new drum before putting it into service
because it trues the drum to the wheel. Technician B says that most heat discoloration and
checking is easy to remove on used drums when brakes are serviced by skimming the drum on a
lathe. Who is correct? correct answers Technician A only
When a safety pop-off valve continuously unloads, which of the following should be performed
first? correct answers The unloader air circuit should be checked
At how much freestroke travel should a properly adjusted, automatic S-cam brake slack adjuster
test? correct answers 3/8 to 5/8 inch
What is the maximum S-cam endplay permitted when installing a slack adjuster? correct answers
0.060 inch
What is the adjustment stroke limit for a 24-Series brake chamber? correct answers 1.75 inches
What is the adjustment stroke limit for a standard 30-Series brake chamber? correct answers 2
inches
what is an anode
A. A diode
B. A transistor
C. A positive terminal
D. A negative terminal correct answers C. A positive terminal
What is a cathode?
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