Tractor and Trailer Air Systems

The trailer air supply control is a red knob used to control the trailer parking valve. What happens when the valve is pulled out?

• The trailer emergency brakes are applied

• The air supply is cut off

• The trailer parking valve closes

• The service line is activated.

What should you do to ensure a proper connection when coupling glad hands?

• Press the two seals together at a 90-degree angle

• Clean the couplers and rubber seals

• Use a blue hose for emergency lines

• Turn the glad hand to lock the couplers.

If the air lines are crossed, what will happen?

• Air will go to the service line

• Air will charge the trailer air tanks

• The trailer spring brakes will release

• The emergency brakes will apply.

What is the normal position of the trailer air supply control valve?

• Pushed in

• Pulled out

• Halfway open

• Closed

When connecting glad hands, what angle should the seals be pressed together?

• 45 degrees

• 60 degrees

• 90 degrees

• 120 degrees

Each trailer and converter dolly has one or more air tanks. They are filled by the ________ line from the tractor.

• emergency (supply)

• service

• brake

• hydraulic

Why is it important to drain air tanks daily?

• To prevent water and oil build-up

• To increase air pressure

• To reduce noise

• To save fuel

What happens if there is a major leak in the emergency line?

• The trailer will speed up

• The trailer will stop immediately

• The trailer parking valve will close

• The trailer lights will turn off.

What is the function of the trailer hand valve?

• To control the trailer brakes

• To fill the air tanks

• To release the parking brake

• To adjust the mirrors.

What is the consequence of a leak in the service line?

• Increased fuel consumption

• Lower air tank pressure

• Faster braking

• Brighter lights