©THESTAR EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
Heavy Truck Brakes test Exam Questions
And Answers Updated 2024/2025
When a truck has no air pressure in its tanks, which warning devices are activated when the
ignition key is turned on? - answer✔A buzzer, a dash gauge and a red light
What legislation mandates every required standard of a highway truck air brake system? -
answer✔FMVSS 121
If a truck is FMVSS 121 compliant, which of the following air reservoirs must be incorporated
into the air brake circuit? - answer✔Supply, primary and secondary tanks
In a truck air brake system which sub circuit is primarily responsible for actuating front axle
service brakes when the system is functioning normally? - answer✔Secondary circuit
When a FMVSS 121 compliant tractor trailer combination is moving down the highway at a
speed of 50 mph, which circuit must be charged with air? - answer✔Hold off circuit
What best describes the functions of a tractor protection valve? - answer✔Pressure protects
the tractor air supply in the event of loss of pressure in a trailer
Routes trailer supply air and service application signal to the trailer pneumatic circuits
Blocks service signal air to the trailer until trailer air supply is activated
If you have yo make an adjustment to air system cut off pressure where should the adjustment
be made? - answer✔The governor
How is the relay section of an FMVSS 121 compliant duel circuit foot valve activated when the
air brake is functioning properly? - answer✔Pneumatically
What is the function of a quick release gladhand when used? - answer✔Speeds service brake
release timing
What best accounts for brake feel in an air brake system? - answer✔Resistance of application
pressure versus for pressure
1|Page
ALL RIGHTS RESERVED.
Heavy Truck Brakes test Exam Questions
And Answers Updated 2024/2025
When a truck has no air pressure in its tanks, which warning devices are activated when the
ignition key is turned on? - answer✔A buzzer, a dash gauge and a red light
What legislation mandates every required standard of a highway truck air brake system? -
answer✔FMVSS 121
If a truck is FMVSS 121 compliant, which of the following air reservoirs must be incorporated
into the air brake circuit? - answer✔Supply, primary and secondary tanks
In a truck air brake system which sub circuit is primarily responsible for actuating front axle
service brakes when the system is functioning normally? - answer✔Secondary circuit
When a FMVSS 121 compliant tractor trailer combination is moving down the highway at a
speed of 50 mph, which circuit must be charged with air? - answer✔Hold off circuit
What best describes the functions of a tractor protection valve? - answer✔Pressure protects
the tractor air supply in the event of loss of pressure in a trailer
Routes trailer supply air and service application signal to the trailer pneumatic circuits
Blocks service signal air to the trailer until trailer air supply is activated
If you have yo make an adjustment to air system cut off pressure where should the adjustment
be made? - answer✔The governor
How is the relay section of an FMVSS 121 compliant duel circuit foot valve activated when the
air brake is functioning properly? - answer✔Pneumatically
What is the function of a quick release gladhand when used? - answer✔Speeds service brake
release timing
What best accounts for brake feel in an air brake system? - answer✔Resistance of application
pressure versus for pressure
1|Page
