CDL Combination Test Exam Questions
With Verified Answers.
If you cross connect the two air lines the following will result - answer✔You will not have air
going to the trailer brakes
You have coupled with a semi-trailer. In what position should you put the front trailer supports
before driving away? - answer✔Fully raised with the crank handle secured in its bracket
Th trailer air supply control: - answer✔Is a red, eight sided knob
A device which connects the service and emergency air lines from the truck to the trailer is
called.. - answer✔Glad hands
If one of the glad hands on your blue air line is missing a seal: - answer✔You might end up with
a service line air leak
In order to supply air to the trailer, you must first: - answer✔Stop engine so you can hear the
brakes
The hand valve should be used: - answer✔To test the trailer brakes
The air leakage rate for a combination vehicle (engine off, brakes on) should not be more than
_______ psi per minute - answer✔4
When should you use the hand valve to park a combination vehicle? - answer✔Never
When you get ready to back under the semi-trailer you should line up - answer✔Directly in front
of the trailer
If the service air line comes apart while you are driving a combination vehicle but the emergency
line stays together, what will happen right away - answer✔Nothing is likely to happen until you
try to apply the brakes
When uncoupling, if you park the trailer at an angle... - answer✔You could do damage to the
landing gear
Which of these statements is true? - answer✔"Bobtail" tractors can take longer to stop than a
combination vehicle loaded to the maximum gross weight
In normal driving, some drivers use the hand valve before applying the brake pedal to prevent a
jackknife. Which of these statements is true? - answer✔It should not be done
When you inspect the coupling, check to ensure that: - answer✔There's a little slack in the air
lines
When backing under a tractor under a trailer you should expect: - answer✔Trailer will be lifted
slightly when the tractor back under it
A king pin is: - answer✔A pin which locks the trailer to the tractor on the fifth wheel
The safety catch for the fifth wheel locking level must be ______ for a coupling to be complete. -
answer✔Over the locking lever
The air leakage rate for a combination vehicle (engine off, brakes off) should be no more than
_____ psi per minute. - answer✔3
You are coupling a tractor to a semi-trailer and have backed up but are not under it. What should
you hook up before backing under? - answer✔The emergency and service air lines
Air lines on a combination vehicle are often colored to keep them from getting mixed up. The
emergency line is ____; the service line is _____. - answer✔Red, blue
You should not back a tractor under a trailer until the whole air system is: - answer✔At normal
pressure
Large combination vehicles take longer to stop: - answer✔When they are empty
In order to inspect the coupling, you should: - answer✔Use a flashlight if necessary
After you supply air to the trailer, make sure the air lines are not crossed and the trailer brakes
are working. This is done by: - answer✔Applying and releasing the trailer brakes and listening
for brake sounds; and also by lifting the brake pedal
The front trailer supports are up and the trailer is resting on the tractor. Make sure: -
answer✔There is enough clearance between the tractor frame and the landing gear and that there
is enough clearance between the tops of the tractor tires and the nose of the trailer
You can damage the landing gear if you: - answer✔Back under the trailer at an angle
After you supply air to the trailer, make sure the airlines are not crossed and the trailer brakes are
working. This is done by: - answer✔Applying and releasing the trailer brakes and listening for
brake sounds
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Brainbarter. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.49. You're not tied to anything after your purchase.
