Coupling, Inspecting and Brake Checks for Doubles

Question 1

The second trailer has no spring brakes. How do you set its emergency brakes before coupling?

Accepted Answer

Drive the tractor close, connect the emergency line, charge the trailer air tank, and disconnect the emergency line

Answer

Connect the service line and leave it connected

Answer

Open the trailer air tank drain

Question 2

You have any doubt about the brakes of the second trailer before coupling. What do you do?

Accepted Answer

Chock the wheels

Answer

Couple faster

Answer

Release the brakes

Question 3

For the safest handling, where should the more heavily loaded semitrailer be?

Accepted Answer

In first position behind the tractor

Answer

In the rear

Answer

Position does not matter

Question 4

One of your two trailers is much lighter than the other. Where does it go?

Accepted Answer

In the rear

Answer

Directly behind the tractor

Answer

Wherever it is quicker to couple

Question 5

How do you release the brakes on a converter dolly that has no spring brakes?

Accepted Answer

Open the air tank petcock

Answer

Pull the dolly parking brake control

Answer

Disconnect the safety chains

Question 6

The dolly is only a short distance from the second trailer. How may you move it into position?

Accepted Answer

Wheel it into position by hand so it is in line with the kingpin

Answer

Push it with the second trailer

Answer

Drag it by the air hoses

Question 7

After hooking the dolly to the front trailer, what do you do with the pintle hook and the converter gear support?

Accepted Answer

Lock the pintle hook and secure the converter gear support in the raised position

Answer

Leave the pintle hook open and the support down

Answer

Remove the support and store it in the cab

Question 8

What is the correct height of the rear trailer before the dolly is pushed under it?

Accepted Answer

Slightly lower than the center of the fifth-wheel, so the trailer is raised slightly

Answer

Well above the fifth-wheel, so the dolly rolls under freely

Answer

Resting on the ground

Question 9

After backing the dolly under the rear trailer, why do you raise the landing gear slightly off the ground?

Accepted Answer

To prevent damage if the trailer moves

Answer

To make the trailer lighter

Answer

To release the trailer brakes

Question 10

How do you test the coupling of the dolly to the rear trailer?

Accepted Answer

Pull against the pin of the second semitrailer

Answer

Open the air tank petcock

Answer

Bounce on the dolly tongue

Question 11

What do you look for in the visual check of the dolly coupling?

Accepted Answer

No space between the upper and lower fifth-wheel, and locking jaws closed on the kingpin

Answer

A small gap between the upper and lower fifth-wheel

Answer

Locking jaws open

Question 12

What do you connect after the visual check of the dolly coupling?

Accepted Answer

The safety chains, air hoses, and light cords

Answer

Only the light cords

Answer

Only the air hoses

Question 13

When coupling doubles, which valves do you close?

Accepted Answer

The converter dolly air tank petcock and the shut-off valves at the rear of the second trailer

Answer

The shut-off valves at the rear of the first trailer

Answer

All shut-off valves on both trailers

Question 14

When coupling doubles, which shut-off valves do you open?

Accepted Answer

Those at the rear of the first trailer, and on the dolly if so equipped

Answer

Those at the rear of the second trailer

Answer

None

Question 15

After coupling doubles and charging the trailer brakes, how do you check for air at the rear of the second trailer?

Accepted Answer

Open the emergency line shut-off

Answer

Open the dolly air tank petcock

Answer

Disconnect the light cord

Question 16

How should the rig be parked for uncoupling the rear trailer?

Accepted Answer

In a straight line, on firm level ground

Answer

At an angle, on a slope

Answer

In a curve, on soft ground

Question 17

When uncoupling the rear trailer, how far do you lower the landing gear of the second semitrailer?

Accepted Answer

Enough to remove some weight from the dolly

Answer

Until the trailer lifts clear of the dolly

Answer

Only until it is halfway down

Question 18

When uncoupling the rear trailer, which air shut-offs do you close?

Accepted Answer

Those at the rear of the first semitrailer, and on the dolly if so equipped

Answer

Those at the rear of the second semitrailer only

Answer

None, they stay open

Question 19

How is the dolly pulled out from under the rear semitrailer?

Accepted Answer

Release the dolly brakes and the dolly fifth-wheel latch, then slowly pull the tractor, first semitrailer, and dolly forward

Answer

Unlock the pintle hook and push the dolly by hand

Answer

Back the first semitrailer into the second

Question 20

Why must you never unlock the pintle hook with the dolly still under the rear trailer?

Accepted Answer

The dolly tow bar may fly up, possibly causing injury, and make it very difficult to recouple

Answer

The trailer lights will go out

Answer

The air tanks will drain

Question 21

When uncoupling the converter dolly, how do you keep it from moving?

Accepted Answer

Apply the converter gear spring brakes or chock the wheels

Answer

Leave it hooked to the safety chains

Answer

Lean it against the first trailer

Question 22

How do you uncouple the third trailer of a triple-trailer rig?

Accepted Answer

Pull the dolly out, then unhitch the dolly using the method for uncoupling doubles

Answer

Unlock the pintle hook first, then pull the dolly out

Answer

Uncouple the first trailer first

Question 23

Your combination is a type the handbook does not describe. How should you couple and uncouple it?

Accepted Answer

Learn the correct way for that vehicle and follow the manufacturer or owner specifications

Answer

Use the tractor-semitrailer steps without change

Answer

Skip the coupling checks

Question 24

On doubles and triples, in what position are the shut-off valves at the rear of the front trailers?

Accepted Answer

Open

Answer

Closed

Answer

Half open

Question 25

On doubles and triples, in what position are the shut-off valves at the rear of the last trailer?

Accepted Answer

Closed

Answer

Open

Answer

Half open

Question 26

In what position must the converter dolly air tank drain valve be?

Accepted Answer

Closed

Answer

Open

Answer

Removed

Question 27

On a set of triples, in what position are the shut-off valves at the rear of the middle trailer?

Accepted Answer

Open

Answer

Closed

Answer

It depends on the load

Question 28

A spare tire is carried on the converter dolly. What do you check?

Accepted Answer

That it is secured

Answer

That it is inflated to double pressure

Answer

That it is removed before driving

Question 29

Where must the pintle-eye of the dolly be?

Accepted Answer

In place in the pintle hook of the trailer, with the pintle hook latched

Answer

Resting on top of the pintle hook

Answer

Hanging on the safety chains

Question 30

What do you check about the safety chains and light cords on doubles?

Accepted Answer

The chains are secured to the trailers and the light cords are firmly connected in the sockets

Answer

The chains are loose and the cords unplugged

Answer

The chains are stored in the cab

Question 31

How do you check the brakes on a double or triple trailer?

Accepted Answer

As you would any combination vehicle, plus the additional doubles and triples checks

Answer

With the hand valve only

Answer

No brake check is needed

Question 32

On doubles, how do you confirm that service pressure goes through all the trailers?

Accepted Answer

With the trailer handbrake or service brake on, open the service line valve at the rear of the last trailer, then close it

Answer

Open the dolly air tank petcock

Answer

Pull out the trailer air supply knob

Question 33

How do you test the trailer emergency brakes on doubles?

Accepted Answer

Charge the system, check that the trailer rolls freely, stop, pull out the trailer air supply control, and pull gently on the trailer

Answer

Disconnect the dolly while moving

Answer

Close all shut-off valves and drive off

Question 34

When testing the trailer service brakes on doubles, what tells you the trailer brakes are connected and working?

Accepted Answer

You feel the brakes come on when you apply the hand control

Answer

The low air warning comes on

Answer

The air supply knob pops out

Questions and answers

The second trailer has no spring brakes. How do you set its emergency brakes before coupling?

You have any doubt about the brakes of the second trailer before coupling. What do you do?

For the safest handling, where should the more heavily loaded semitrailer be?

One of your two trailers is much lighter than the other. Where does it go?

How do you release the brakes on a converter dolly that has no spring brakes?

The dolly is only a short distance from the second trailer. How may you move it into position?

After hooking the dolly to the front trailer, what do you do with the pintle hook and the converter gear support?

What is the correct height of the rear trailer before the dolly is pushed under it?

After backing the dolly under the rear trailer, why do you raise the landing gear slightly off the ground?

How do you test the coupling of the dolly to the rear trailer?

What do you look for in the visual check of the dolly coupling?

What do you connect after the visual check of the dolly coupling?

When coupling doubles, which valves do you close?

When coupling doubles, which shut-off valves do you open?

After coupling doubles and charging the trailer brakes, how do you check for air at the rear of the second trailer?

How should the rig be parked for uncoupling the rear trailer?

When uncoupling the rear trailer, how far do you lower the landing gear of the second semitrailer?

When uncoupling the rear trailer, which air shut-offs do you close?

How is the dolly pulled out from under the rear semitrailer?

Why must you never unlock the pintle hook with the dolly still under the rear trailer?

When uncoupling the converter dolly, how do you keep it from moving?

How do you uncouple the third trailer of a triple-trailer rig?

Your combination is a type the handbook does not describe. How should you couple and uncouple it?

On doubles and triples, in what position are the shut-off valves at the rear of the front trailers?

On doubles and triples, in what position are the shut-off valves at the rear of the last trailer?

In what position must the converter dolly air tank drain valve be?

On a set of triples, in what position are the shut-off valves at the rear of the middle trailer?

A spare tire is carried on the converter dolly. What do you check?

Where must the pintle-eye of the dolly be?

What do you check about the safety chains and light cords on doubles?

How do you check the brakes on a double or triple trailer?

On doubles, how do you confirm that service pressure goes through all the trailers?

How do you test the trailer emergency brakes on doubles?

When testing the trailer service brakes on doubles, what tells you the trailer brakes are connected and working?

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