ELDT - Entry Level Driver Training Coupling and Uncoupling Questions and Answers 3 — Questions and Answers

Question 1: What should you inspect on the fifth wheel before coupling?

The fifth wheel should be tilted slightly forward
The fifth wheel plate should be greased and the jaws should be open (Correct answer)
The fifth wheel should be raised to its highest position
The fifth wheel mounting bolts should be loosened

Correct answer: The fifth wheel plate should be greased and the jaws should be open

The fifth wheel plate needs adequate grease to reduce friction and prevent wear, and the jaws must be open to accept the kingpin during coupling.

Before coupling, the fifth wheel must be inspected for several things: the plate surface should be properly greased to allow the trailer to articulate smoothly during turns; the locking jaws must be in the open position ready to receive the kingpin; the tilt mechanism should allow the fifth wheel to tilt slightly for different trailer heights; and all mounting bolts must be secure. A dry fifth wheel causes excessive wear and can make steering difficult.

Question 2: When coupling, what gear should the tractor be in when backing under the trailer?

Reverse at idle speed
The lowest reverse gear (Correct answer)
Any reverse gear as long as you go slowly
Neutral with the parking brake off

Correct answer: The lowest reverse gear

Using the lowest reverse gear gives maximum control and the slowest speed, which is critical for precise alignment with the kingpin.

When backing under a trailer to couple, drivers must use the lowest reverse gear available. This provides the slowest speed and greatest control, which is essential for precise alignment with the trailer kingpin. Backing too fast can result in the tractor striking the trailer with excessive force, potentially damaging the kingpin, fifth wheel, or trailer nose. The driver should feather the clutch and brake to maintain a very slow, controlled approach.

Question 3: After connecting the air lines during coupling, what should you do next?

Immediately drive away
Raise the landing gear
Charge the trailer air system and check for leaks (Correct answer)
Disconnect and reconnect the electrical line

Correct answer: Charge the trailer air system and check for leaks

After connecting air lines, you must supply air to the trailer brake system and check all connections for leaks before the vehicle is road-ready.

Once the air lines (glad hands) are connected, the driver must charge the trailer air system by supplying air from the tractor. During this process, the driver should listen and feel for air leaks at the glad hand connections and along the trailer air lines. The air pressure gauge should build to the correct operating range. Any leaks must be repaired before driving. This step is critical because inadequate air pressure means the trailer brakes will not function properly.

Question 4: Why is it important to check under the trailer after uncoupling?

To verify the landing gear pads are on solid ground (Correct answer)
To look for fuel leaks
To check for animals
To inspect the tractor exhaust system

Correct answer: To verify the landing gear pads are on solid ground

The landing gear pads must rest on solid, level ground to properly support the trailer weight. Soft ground can cause the pads to sink and the trailer to tip.

After uncoupling and before pulling the tractor away, the driver should verify that the landing gear pads are resting on firm, level ground. If the pads are on soft soil, gravel, or hot asphalt, they can sink under the weight of the trailer, causing it to lean or even tip over. In such cases, boards or pads should be placed under the landing gear. The driver should also verify that the trailer is not leaning to one side and that the landing gear is properly locked in position.

Question 5: What is the correct order for connecting airlines and electrical cord during coupling?

Electrical cord first, then air lines
Air lines first, then electrical cord (Correct answer)
Both at the same time
The order does not matter

Correct answer: Air lines first, then electrical cord

Air lines should be connected first to establish brake functionality before connecting the electrical cord, ensuring safety systems are operational first.

The standard coupling procedure calls for connecting the air lines before the electrical cord. This sequence prioritizes the brake system, which is the most critical safety system. By connecting air lines first, the trailer brakes can be charged and tested before the vehicle moves. The electrical cord, which powers the trailer lights, is connected afterward. Some experienced drivers may vary this order, but FMCSA training materials recommend air lines first for safety.

Question 6: What could happen if you forget to remove the wheel chocks before pulling the tractor away during uncoupling?

The trailer may roll forward
The tractor tires could be damaged (Correct answer)
Nothing, chocks are not used during uncoupling
The fifth wheel could be damaged

Correct answer: The tractor tires could be damaged

Wheel chocks placed at the tractor tires during uncoupling must be removed before driving away, otherwise the tires could be damaged when driving over them.

During uncoupling, wheel chocks may be placed at the tractor drive tires or trailer tires for added safety. If the driver forgets to remove chocks from the tractor tires before pulling away, driving over or into the chocks can damage the tires, potentially causing sidewall damage or blowouts. For trailer chocks, they should remain in place until the trailer is ready to be moved by another tractor. Part of the post-uncoupling procedure is a walk-around to collect all equipment.

ELDT - Entry Level Driver Training Coupling and Uncoupling Questions and Answers 3

What should you inspect on the fifth wheel before coupling?