Questions and Answers
You supply air to the trailer tanks by?
A driver crosses the air lines when hooking up to an old trailer with no spring brakes. What will happen?
Gland hands are used to connect the:
After you connect the air lines, but before you back under the trailer, you should?
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To unlock the fifth wheel pull the release handle to the______ position.
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For a coupling to be complete, the safety catch for the fifth wheel locking lever must be?
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Which part of the kingpin should the locking jaws close around?
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Why should you be sure that the fifth wheel plate is greased as required?
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When should you use the hand valve to park a combination vehicle?
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The trailer air supply should automatically close when the air pressure falls to between_____ Psi.
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The best way to tell if your trailer has started to skid is to?
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When coupling, the proper position of the fifth wheel is?
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A trailer is most likely to jackknife when it is?
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If the spring brakes don't release when you push the trailer air supply control, you should?
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The front trailer supports are up and the trailer is resting on the tractor; make sure?
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Total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to______ distance.
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Some air brake systems have an alcohol evaporator. What may happen if you don't keep the unit filled with alcohol?
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What is emergency stab braking?
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Study Notes
Air Supply and Trailer Coupling
- Air is supplied to the trailer tanks by pushing in the trailer air supply valve.
- When air lines are crossed during hookup to an old trailer without spring brakes, the driver could end up driving away without trailer brakes.
- Gland hands are used to connect service and emergency air lines from the truck to the trailer.
Pre-Coupling Checks
- After connecting air lines but before backing under the trailer, supply air to the trailer system and then pull the air supply knob.
Fifth Wheel Operations
- To unlock the fifth wheel, pull the release handle to the open position.
- For a complete coupling, ensure the safety catch for the fifth wheel locking lever is over the locking lever.
- The locking jaws should close around the head of the kingpin, referred to as "the shark".
Vehicle Control and Safety
- Greasing the fifth wheel plate prevents steering problems.
- The hand valve should never be used to park a combination vehicle.
- The trailer air supply automatically closes when air pressure falls between 20 and 45 PSI.
Skidding and Coupling Position
- The best way to detect if a trailer has started to skid is by observing it in your mirrors.
- During coupling, the fifth wheel should be tilted down towards the end of the tractor.
- A trailer is most likely to jackknife when it is empty.
Brake Systems and Maintenance
- If spring brakes do not release after pushing the trailer air supply control, check the air connection lines.
- Ensure there is enough clearance between the tractor frame and landing gear when the trailer is resting on the tractor.
- Air brake vehicles experience longer total stopping distances due to brake lag.
Alcohol Evaporators and Emergency Braking
- In air brake systems with an alcohol evaporator, lack of alcohol could lead to ice formation in air storage tanks, causing brake failure.
- Emergency stab braking involves braking hard, releasing once the wheels lock, and reapplying when they start rolling.
Service Brake Check
- Regularly check that service brakes are functioning properly to ensure safety.
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Description
Test your knowledge for the CDL Class A License with these flashcards. Cover essential topics, including air supply to trailer tanks and handling air line connections. Perfect for drivers preparing for the licensing exam.
