Reading Flashcards

Reading the function of spring brakes, how do they apply when air pressure is lost?

Answer: Powerful springs apply the brakes mechanically

When air pressure is released, powerful springs apply the spring (emergency/parking) brakes mechanically.

What does the manual warn never to do with the spring brakes engaged?

Answer: Apply the service brake pedal at the same time, which can damage the brakes

Pressing the service brake while spring brakes are applied can combine forces and damage the brakes.

According to the text, what is the purpose of the tractor protection valve?

Answer: To keep tractor air if the trailer breaks away or leaks badly

The tractor protection valve keeps air in the tractor brake system if the trailer breaks away or develops a bad leak.

Reading about the trailer air supply control, what color and shape is the knob typically?

Answer: Eight-sided red knob

The trailer air supply control is usually a red, eight-sided knob.

What does the trailer hand valve (trolley valve) operate?

Answer: Only the trailer brakes

The trailer hand valve works only the trailer brakes and should not be used for parking.

Per the guidance, why should the trailer hand valve not be used for parking?

Answer: Leaks may release the brakes; spring brakes should hold the vehicle

Air may leak out and release the hand valve brakes, so spring brakes should be used to hold a parked vehicle.

When the manual describes draining air tanks, why is this necessary?

Answer: To remove water and oil that collect from compressed air

Air tanks must be drained to remove water and compressor oil that accumulate and can harm the system.