ASE T4 brakes EXAM QUESTIONS WITH |\ |\ |\ |\ |\ |\
ANSWERS
The low air pressure indicator light and buzzer stay on
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
with the air pressure gauges showing 100 psi. Which of
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
these could be the cause? |\ |\ |\ |\ |\
(A) A failed double check valve
|\ |\ |\ |\ |\
(B) A leaking spring brake chamber
|\ |\ |\ |\ |\
(C) A leaking parking brake control valve
|\ |\ |\ |\ |\ |\
(D) A failed low air pressure sensor - CORRECT ANSWERS
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✔✔Explanation: The gauge reading of 100 psi indicates |\ |\ |\ |\ |\ |\ |\ |\
pressure well above the low-pressure sensor threshold. As
|\ |\ |\ |\ |\ |\ |\
a result, options A, B, and C will not cause the light and
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
buzzer to stay ON. The answer is D. |\ |\ |\ |\ |\ |\ |\
Which of these could cause the tractor system air
|\ |\ |\ |\ |\ |\ |\ |\ |\
pressure to drop to zero psi after a trailer emergency line
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
breaks? |\
|\
|\ (A) A saturated air drier
|\ |\ |\ |\
,(B) A failed tractor protection valve
|\ |\ |\ |\ |\
(C) A brake application valve not exhausting
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(D) A failed trailer service control valve - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔Explanation: A failed tractor protection |\ |\ |\ |\ |\ |\
valve will cause air pressure in the tractor braking system
|\ |\ |\ |\ |\ |\ |\ |\ |\
to escape after a trailer air line failure. Options A, C, and
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D will not cause the tractor system air pressure to drop to
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
zero psi. The answer is B.
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After the air drier purges, the primary air pressure gauge
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
reads 120 psi and the secondary gauge reads 90 psi. No
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
leaks in the system are observed. Which of these could
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
be the cause?
|\ |\ |\
|\
|\ (A) A stuck-open air compressor unloader valve
|\ |\ |\ |\ |\ |\
(B) A failed air compressor governor
|\ |\ |\ |\ |\
(C) A failed gauge in the instrument cluster
|\ |\ |\ |\ |\ |\ |\ |\
(D) A seized parking brake control valve - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔Explanation: The primary and secondary |\ |\ |\ |\ |\ |\
, pressure gauges should read the same pressures in a |\ |\ |\ |\ |\ |\ |\ |\ |\
normalized state. Options A and B will affect both gauges |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
equally. Option D will have no effect on the system |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
pressures. The answer is C. |\ |\ |\ |\
A truck that has the air compressor inlet connected to the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
engine air cleaner housing has excessive oil in the air
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
brake system. This could be caused by:
|\ |\ |\ |\ |\ |\ |\
|\
|\ (A) worn air compressor piston rings.
|\ |\ |\ |\ |\
(B) a restricted turbocharger oil supply line.
|\ |\ |\ |\ |\ |\
(C) misadjusted brake chamber stroke.
|\ |\ |\ |\
(D) a leaking air control line - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔Explanation: Worn compressor piston rings can allow |\ |\ |\ |\ |\ |\ |\
oil to enter the pumping chamber during the intake
|\ |\ |\ |\ |\ |\ |\ |\ |\
stroke. This will cause excessive oil to be present in the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
air brake system. Options B, C, and D will not cause oil to
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
be present in the air brake system. The answer is A.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
With the truck running and the air compressor pumping
|\ |\ |\ |\ |\ |\ |\ |\ |\
continuously, the air system will not build air pressure. |\ |\ |\ |\ |\ |\ |\ |\ |\
Which of these could be the cause? |\ |\ |\ |\ |\ |\ |\
|\
ANSWERS
The low air pressure indicator light and buzzer stay on
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
with the air pressure gauges showing 100 psi. Which of
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
these could be the cause? |\ |\ |\ |\ |\
(A) A failed double check valve
|\ |\ |\ |\ |\
(B) A leaking spring brake chamber
|\ |\ |\ |\ |\
(C) A leaking parking brake control valve
|\ |\ |\ |\ |\ |\
(D) A failed low air pressure sensor - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔Explanation: The gauge reading of 100 psi indicates |\ |\ |\ |\ |\ |\ |\ |\
pressure well above the low-pressure sensor threshold. As
|\ |\ |\ |\ |\ |\ |\
a result, options A, B, and C will not cause the light and
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
buzzer to stay ON. The answer is D. |\ |\ |\ |\ |\ |\ |\
Which of these could cause the tractor system air
|\ |\ |\ |\ |\ |\ |\ |\ |\
pressure to drop to zero psi after a trailer emergency line
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
breaks? |\
|\
|\ (A) A saturated air drier
|\ |\ |\ |\
,(B) A failed tractor protection valve
|\ |\ |\ |\ |\
(C) A brake application valve not exhausting
|\ |\ |\ |\ |\ |\
(D) A failed trailer service control valve - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔Explanation: A failed tractor protection |\ |\ |\ |\ |\ |\
valve will cause air pressure in the tractor braking system
|\ |\ |\ |\ |\ |\ |\ |\ |\
to escape after a trailer air line failure. Options A, C, and
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
D will not cause the tractor system air pressure to drop to
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
zero psi. The answer is B.
|\ |\ |\ |\ |\ |\
After the air drier purges, the primary air pressure gauge
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
reads 120 psi and the secondary gauge reads 90 psi. No
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
leaks in the system are observed. Which of these could
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
be the cause?
|\ |\ |\
|\
|\ (A) A stuck-open air compressor unloader valve
|\ |\ |\ |\ |\ |\
(B) A failed air compressor governor
|\ |\ |\ |\ |\
(C) A failed gauge in the instrument cluster
|\ |\ |\ |\ |\ |\ |\ |\
(D) A seized parking brake control valve - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔Explanation: The primary and secondary |\ |\ |\ |\ |\ |\
, pressure gauges should read the same pressures in a |\ |\ |\ |\ |\ |\ |\ |\ |\
normalized state. Options A and B will affect both gauges |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
equally. Option D will have no effect on the system |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
pressures. The answer is C. |\ |\ |\ |\
A truck that has the air compressor inlet connected to the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
engine air cleaner housing has excessive oil in the air
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
brake system. This could be caused by:
|\ |\ |\ |\ |\ |\ |\
|\
|\ (A) worn air compressor piston rings.
|\ |\ |\ |\ |\
(B) a restricted turbocharger oil supply line.
|\ |\ |\ |\ |\ |\
(C) misadjusted brake chamber stroke.
|\ |\ |\ |\
(D) a leaking air control line - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔Explanation: Worn compressor piston rings can allow |\ |\ |\ |\ |\ |\ |\
oil to enter the pumping chamber during the intake
|\ |\ |\ |\ |\ |\ |\ |\ |\
stroke. This will cause excessive oil to be present in the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
air brake system. Options B, C, and D will not cause oil to
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
be present in the air brake system. The answer is A.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
With the truck running and the air compressor pumping
|\ |\ |\ |\ |\ |\ |\ |\ |\
continuously, the air system will not build air pressure. |\ |\ |\ |\ |\ |\ |\ |\ |\
Which of these could be the cause? |\ |\ |\ |\ |\ |\ |\
|\
