ABS TCS Test 1|42 Questions with
100% Accurate Answers
supply, primary, and secondary tanks - - If a truck is FMVSS 121 compliant,
which of the following air reservoirs must be incorporated into the air brake
circuit?
a. wet tank, supply tank, and air start tanks
b. front brake and rear brake tanks
c. supply, primary, and secondary tanks
d. wet tank and purge tanks
- secondary circuit - - In a truck air brake system, which sub-circuit is
primarily responsible for actuating front axle service brakes when the system
is functioning normally?
a. primary circuit
b. supply circuit
c. secondary circuit
d. wet circuit
- cut-out at 125 psi and cut-in at 100 psi - - Which of the following pressure
values are FMVSS-121 compliant for governor cut-out and cut-in pressures?
a. cut-out at 125 psi and cut-in at 100 psi
b. cut-out at 115 psi and cut-in at 85 psi
c. cut-out at 110 psi and cut-in at 80 psi
d. cut-out at 135 psi and cut-in at 90 psi
- governor - - If you have to make an adjustment to air system cut-out
pressure, where should the adjustment be made?
a. governor
b. pressure protection valve
c. dryer purge valve
d. unloader valve
- remote controlled service brake valve - - What is the primary function of a
relay valve?
a. routes hold-off air to the hold-off chambers
b. remote controlled service brake valve
c. relays pressure from the primary circuit to the secondary circuit
d. relays governor signal pressure to the unloader pistons
, - all of the above - - Which of the following factors can affect the timing of
service brakes?
a. relay valve crack pressures
b. hose and tubing diameters and length
c. replacing a 45-degree fitting with a 90-degree fitting
d. all of the above
- anti-compounding - - When a tractor spring brake assembly is charged
with air on both its service and hold-off chambers, what results is known as:
a. proportioning
b. service braking only
c. park braking only
d. anti-compounding
- pop-off valve - - Which of the following terms is often used to describe a
truck safety pressure relief valve?
a. quick release valve
b. emergency relay valve
c. inversion valve
d. pop-off valve
- 150 psi - - What pressure is a pop-off valve set to trip at in most highway
truck applications?
a. governor cut-in pressure
b. 125 psi
c. 150 psi
d. governor cut-out pressure
- Both A and B - - Technician A says that in the event of a total failure of the
primary circuit in an FMVSS-121 compliant tractor-trailer combination, the rig
can be brought safely to a complete stop. Technician B says that in the event
of a total failure of the primary circuit the relay section of the treadle valve
will be actuated mechanically. Who is correct?
a. Technician A only
b. Technician B only
c. Both A and B
d. Neither A nor B
- Technician A only - - Technician A says that current air brake systems are
designed to bring a fully loaded tractor trailer combination safely to a
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