ELDT Coupling and Uncoupling 2

Question 1

Before backing under a trailer, where should the fifth wheel plate be positioned relative to the trailer's apron?

Accepted Answer

Slightly lower than the trailer apron

Answer

The fifth wheel should be low enough that the tractor lifts the trailer slightly as you back under it, ensuring the kingpin engages properly.

Question 2

What is the correct height for the trailer before backing the tractor under it?

Accepted Answer

So the trailer is raised slightly when the tractor backs under

Answer

The trailer should be at a height where the tractor raises it slightly when backing under, guaranteeing solid kingpin contact.

Question 3

When testing the coupling by pulling forward gently against the locked kingpin, this is called a:

Accepted Answer

Tug test

Answer

The tug test involves gently pulling the tractor forward against the locked fifth wheel to confirm the kingpin is secured.

Question 4

Which color glad hand or line typically supplies the emergency (supply) air to the trailer?

Accepted Answer

Red

Answer

The red line/glad hand is the emergency supply line that charges the trailer air tanks and controls the spring brakes.

Question 5

What should you do with the tractor parking brake before crawling under to inspect the coupling?

Accepted Answer

Apply it and chock the wheels if needed

Answer

Always apply the parking brakes before going under the vehicle to prevent it from rolling and crushing you.

Entry Level Driver Training (ELDT) Practice Test