T4 ASE Delmar practice test
#2 with 100% correct
answers
Technician A says the same electronic control unit (ECU) operates the
antilock braking systems (ABSs) on the tractor and the trailer. Technician
B says that if replacement tires are of different size from there original
tires, the wheel speed sensor signals are affected. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Correct Answer is B: Only technician B is corrrect. If the replacement tires
are a different size copared to the original tire, the wheel speed sensor
signals are affected.
A truck with air brakes and a suspended (firewall-mounted) pedal has a
low pedal. Which of the following could be the cause?
A. The brakes are adjusted too tight.
B. No air pressure in the primary brake circuit
C. The brake pedal pushrod is too long
D. The parking brake is broken
Correct Answer is B: When there is a failure in the primary brake circuit,
the primary piston will mechanically travel in the bore and push the
secondary piston to operate the secondary brakes. This will cause the
driver to feel the pedal traveling farther than normal, thus resulting in a
low pedal.
*Referring to the figure above, there is an air leak from the service relay
when the parking brakes are released using the dash-mounted valve.
Technician A says the service relay may be faulty. Technician B says the
parking brake chamber may be faulty. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Correct Answer is B: The parking brake chambers is allowing air through
the center seal and it is following back into the service relay valve. The
open exhaust of the service relay valve is allowing the air to escape. The
parking brake chamber will need to be replaced.
, A truck with hydraulic disc brakes has dragging brakes. Technician A says
the calipers may be sticking. Technician B says the master cylinder may be
passing fluid. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither. A nor B
Correct Answer is A: Sticking caliper slides can cause the brakes to drag
Which of the following could cause one brake on a truck to wear faster
than the others?
A. A restricted service brake hose
B. A restricted air line between the supply and primary tank
C. Low air pressure in the service tanks
D. Governor cut-out pressure too high
Correct Answer is A: A restricted service brake hose would allow unequal
brake applications and thus unequal brake wear. Also, the air would not be
able to release from the brake chamber, causing that brake to drag.
The front brakes on a truck are being checked. The drum rolls freely
backward but hangs and stops when rotated forward by hand. Technician
A says the problem could be broken slack adjuster. Technician B says the
problem could be an incorrectly adjusted hand brake valve. Who is
correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Correct Answer is D: Both technicians are incorrect. This indicates a
broken return spring
On a tractor with air brakes, the parking brake on the tractor will not
release, but the trailer brakes work correctly. Which of the following is the
most likely cause?
A. Shorted brake light switch
B. Stuck parking brake relay valve
C. Stuck service brake relay valve
D. A hand valve slightly stuck on
Correct Answer is B: A stuck tractor parking brake relay valve could
prevent air from entering the spring brake chamber and prevent the
parking brake from releasing.
A technician is testing a hydraulic brake booster. With the engine off, the
brake pedal depresses 1.5 inches, then the engine is started and the
brake pedal falls another inch. Technician A says this indicates a faulty
master cylinder. Technician B says this indicates a faulty brake booster.
#2 with 100% correct
answers
Technician A says the same electronic control unit (ECU) operates the
antilock braking systems (ABSs) on the tractor and the trailer. Technician
B says that if replacement tires are of different size from there original
tires, the wheel speed sensor signals are affected. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Correct Answer is B: Only technician B is corrrect. If the replacement tires
are a different size copared to the original tire, the wheel speed sensor
signals are affected.
A truck with air brakes and a suspended (firewall-mounted) pedal has a
low pedal. Which of the following could be the cause?
A. The brakes are adjusted too tight.
B. No air pressure in the primary brake circuit
C. The brake pedal pushrod is too long
D. The parking brake is broken
Correct Answer is B: When there is a failure in the primary brake circuit,
the primary piston will mechanically travel in the bore and push the
secondary piston to operate the secondary brakes. This will cause the
driver to feel the pedal traveling farther than normal, thus resulting in a
low pedal.
*Referring to the figure above, there is an air leak from the service relay
when the parking brakes are released using the dash-mounted valve.
Technician A says the service relay may be faulty. Technician B says the
parking brake chamber may be faulty. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Correct Answer is B: The parking brake chambers is allowing air through
the center seal and it is following back into the service relay valve. The
open exhaust of the service relay valve is allowing the air to escape. The
parking brake chamber will need to be replaced.
, A truck with hydraulic disc brakes has dragging brakes. Technician A says
the calipers may be sticking. Technician B says the master cylinder may be
passing fluid. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither. A nor B
Correct Answer is A: Sticking caliper slides can cause the brakes to drag
Which of the following could cause one brake on a truck to wear faster
than the others?
A. A restricted service brake hose
B. A restricted air line between the supply and primary tank
C. Low air pressure in the service tanks
D. Governor cut-out pressure too high
Correct Answer is A: A restricted service brake hose would allow unequal
brake applications and thus unequal brake wear. Also, the air would not be
able to release from the brake chamber, causing that brake to drag.
The front brakes on a truck are being checked. The drum rolls freely
backward but hangs and stops when rotated forward by hand. Technician
A says the problem could be broken slack adjuster. Technician B says the
problem could be an incorrectly adjusted hand brake valve. Who is
correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Correct Answer is D: Both technicians are incorrect. This indicates a
broken return spring
On a tractor with air brakes, the parking brake on the tractor will not
release, but the trailer brakes work correctly. Which of the following is the
most likely cause?
A. Shorted brake light switch
B. Stuck parking brake relay valve
C. Stuck service brake relay valve
D. A hand valve slightly stuck on
Correct Answer is B: A stuck tractor parking brake relay valve could
prevent air from entering the spring brake chamber and prevent the
parking brake from releasing.
A technician is testing a hydraulic brake booster. With the engine off, the
brake pedal depresses 1.5 inches, then the engine is started and the
brake pedal falls another inch. Technician A says this indicates a faulty
master cylinder. Technician B says this indicates a faulty brake booster.
