Combination Vehicles Test Flashcards
Charge the trailer air brake system and push in the air supply knob. Shut the engine off. Pump the brake pedal several times to reduce the air pressure in the tanks. The trailer air supply control should pop out when the air pressure falls into the range specified by the manufacturer.
This is a tractor protection valve test.
The “Trailer Air Supply” control valve in the cab controls the tractor protection valve.
True.
Check for normal air pressure, release the parking brakes, move the vehicle forward slowly, and apply trailer brake with the hand control trolley valve, if so equipped.
This is how can you test the trailer service brakes.
Which of the following best describes what the trailer air supply control does?
You push it in to supply the trailer with air and pull it out to shut the air off and put on the trailer emergency brakes.
Describe what the service line is for.
The service line carries air, which is controlled by the foot brake or the trailer handbrake.
Which air supply line carries air that is controlled by the trailer handbrake?
Service.
Why should you use tire chocks when parking a trailer without spring brakes?
If the air supply in the trailer air tank has leaked away, there will be no emergency brakes enabling the trailer wheels to turn freely.
Which air supply line carries air to the trailer air tanks?
Emergency.
Never back under a trailer at an angle to couple because you might ____________.
Damage the landing gear.
