T4 ASE BRAKES (MEDIUM/HEAVY
DUTY BRAKES) EXAM QUESTIONS
AND ANSWERS
There is an audible air leak says the double check valve may be faulty. Technician B says the single from
under the dash when the foot valve is applied. Technician A check valve may be faulty. Who is correct? -
ANSWER - Neither Answer A is correct. A leaking double-check valve could allow air to flow to the foot
valve and out the open exhaust. Answer B is incorrect. Single-check valves are used to protect the tanks.
They do not cause an air leak when the brakes are applied. Answer incorrect.
On a straight truck equipped with air brakes, the secondary tank pressure gauge falls to zero when the
wet air tank is drained. Technician A says the one-way check valve may be faulty Technician B says the
foot valve may be faulty. Who is correct? - ANSWER - D. Neither Answer A is correct. The one-way check
valve should protect the secondary tank. The check valve is leaking. Answer B is incorrect. The foot valve
does not separate the wet and secondary tanks. Answer C is incorrect. Technician B is incorrect. Answer
D is incorrect. Technician A is correct.
Which of the following could set an antilock braking system (ABS) wheel speed sensor code A. Faulty
modulator hold solenoid B. Faulty modulator release solenoid C. Incorrect wheel bearing adjustment D.
Incorrect brake adjustment - ANSWER - Answer A is incorrect. A faulty solenoid would not cause a wheel
speed sensor code. It could cause a modulator valve code Answer B is incorrect. A faulty solenoid would
not cause a wheel speed sensor code. It conld cause a modulator valve code. Answer C is correct. A
loose wheel bearing adjustment can cause a faulty wheel speed sensor and a wheel speed sensor code
Answer D is incorrect An incorrect brake adjustment may cause a dragging brake bt would not cause a
wheel specd sensor code
The air drier purges to often. Technician A says B says a leaking wet tank the air drier delivery could be
the cause. Who is correct? - ANSWER - Answer C is correct. A leaking air drier check valve will allow the
wet tank to drain back through the air drier. This will cause air compressor will again build tank pressure
and unload, pressure to drop t to governor cut-in rapidly. The air and the sequence will start over. A
leaking wet tank will cause the air pressure to fall rapidly and the compressor to build air again and then
cut out. This too will cause the air drier to purge often.
DUTY BRAKES) EXAM QUESTIONS
AND ANSWERS
There is an audible air leak says the double check valve may be faulty. Technician B says the single from
under the dash when the foot valve is applied. Technician A check valve may be faulty. Who is correct? -
ANSWER - Neither Answer A is correct. A leaking double-check valve could allow air to flow to the foot
valve and out the open exhaust. Answer B is incorrect. Single-check valves are used to protect the tanks.
They do not cause an air leak when the brakes are applied. Answer incorrect.
On a straight truck equipped with air brakes, the secondary tank pressure gauge falls to zero when the
wet air tank is drained. Technician A says the one-way check valve may be faulty Technician B says the
foot valve may be faulty. Who is correct? - ANSWER - D. Neither Answer A is correct. The one-way check
valve should protect the secondary tank. The check valve is leaking. Answer B is incorrect. The foot valve
does not separate the wet and secondary tanks. Answer C is incorrect. Technician B is incorrect. Answer
D is incorrect. Technician A is correct.
Which of the following could set an antilock braking system (ABS) wheel speed sensor code A. Faulty
modulator hold solenoid B. Faulty modulator release solenoid C. Incorrect wheel bearing adjustment D.
Incorrect brake adjustment - ANSWER - Answer A is incorrect. A faulty solenoid would not cause a wheel
speed sensor code. It could cause a modulator valve code Answer B is incorrect. A faulty solenoid would
not cause a wheel speed sensor code. It conld cause a modulator valve code. Answer C is correct. A
loose wheel bearing adjustment can cause a faulty wheel speed sensor and a wheel speed sensor code
Answer D is incorrect An incorrect brake adjustment may cause a dragging brake bt would not cause a
wheel specd sensor code
The air drier purges to often. Technician A says B says a leaking wet tank the air drier delivery could be
the cause. Who is correct? - ANSWER - Answer C is correct. A leaking air drier check valve will allow the
wet tank to drain back through the air drier. This will cause air compressor will again build tank pressure
and unload, pressure to drop t to governor cut-in rapidly. The air and the sequence will start over. A
leaking wet tank will cause the air pressure to fall rapidly and the compressor to build air again and then
cut out. This too will cause the air drier to purge often.
