Tractor and straight truck spring brakes will apply fully when air pressure drops to a range of ____psi.
A. 20-50
B. 30-45
C. 20-45
Answer: C. 20-45
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- Compared with a straight truck or bus, there are ___ things to inspect in combination vehicles
- The service line
- You should not back a tractor under a trailer until the whole air system is
- You are coupling a tractor to a semi-trailer. You have connected the air lines. Before backing under the trailer, you should
- For coupling to be completed, the safety catch for the fifth wheel locking lever must be
- The trailer hand valve works the trailer brakes. Which of these statements is true?
- You should not use the trailer hand valve while driving because
- What is the emergency air line?
- After the trailer has been coupled to the tractor, the tractor protection control valve should be placed in what position?
- You supply air to the trailer tanks by
- Glad hands are used to connect the
- Under good driving conditions, you should leave at least one second of space between your vehicle and the vehicle ahead for every ___ feet of your vehicle's length
- 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
- You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You would expect the trailer brakes to come on and
- A trailer is most likely to jackknife when it is
- The front trailer supports are up, and the trailer is resting on the tractor. Make sure that
- Air lines on a combination vehicle are often colored to keep them from getting mixed up. The emergency line is ___; the service line is ___.
- While you are driving, your emergency air line breaks or gets pulled apart. The loss of pressure will cause the
- Describe what the trailer air supply controls does
- If the brakes did not release when you pushed the trailer air supply valve, you should
- You have a major leak in the service line, and you apply the brakes. Service air pressure will escape and cause the
- After connecting the air lines but before backing under the trailer, you should
- What is the emergency air line for?
- Which of the following is true about off-tracking or "cheating?"
- In general, the higher your truck's center of gravity, the
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