Stopping the Big Rigs - Quiz 8
A tractor differs from a truck because:
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Truck , bus and trailer reform act
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FMVSS-121
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CVSA Checklist
The trailer supply dash valve has:
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A round blue know
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An octagonal blue know
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A yellow know
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None of the above
FMVSS-121 law requires that the tractor's air system be protect from a trailer breakaway between 20 psi and 45 psi. This is why trailer dash supply valves in most cases are pressure sensitive.
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True
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False
The Haldex Modular dash valve
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Is two dash valve in one
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Has a built-in two check valve
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Allows you to park the tractor separate of the trailer.
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All of the above
The function of a tractor protection valve is to:
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Protect the trailer's air system
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Keeps 20 to 45 psi in the tractor's air system if the trailer should break away
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Protect the tractor and if a non-automatic tractor protection valve is used the pressure sensitive dash valve will pop between 20 and 45 psi
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All of the above
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All but A
Haldex tractor protection valves:
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Have a relay built-in feature
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Have larger ports
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Have a quick release feature built-in which releases the trailer brakes faster, giving additional brake lining life
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None of the above
The hand control valve:
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Controls the park brakes
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Allows the driver to make a service application on the trailer, independent of the tractor
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Is used to park
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None of the above
The two-way check valve between the hand control valve and the foot valve seeks out the dominant pressure and sends it to the trailer's service brakes
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True
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False