FREE MS CDL Combination Test (2024)

1. When uncoupling a trailer, after shutting off the trailer air supply to lock the trailer brakes, you should:

pull the tractor forward until the fifth-wheel comes out from under the trailer.
inspect the trailer supports.
back up gently to ease the pressure on the fifth-wheel locking jaws.
immediately apply your tractor parking brakes.

2. With brake drums, if brakes become too hot:

the air compressor will kick on to cool the brakes.
the brakes may stop working.
your ABS will malfunction.
the brakes will supply too much power to the drive wheels.

3. After starting the engine, oil pressure should rise to a normal level:

4. When you get ready to back under the semi-trailer, you should:

back under the trailer at an angle to avoid pushing the trailer sideways.
line up about 15 degrees off the line of the trailer.
line up the kingpin to engage the driver's side locking jaw first.
line up directly in front of the trailer.

5. When driving with cargo, you should re-check the cargo and securing devices as often as necessary to keep the load secure, and inspect again:

6. Dollies with ABS are required to have a malfunction lamp:

7. Which of the following is NOT part of the procedure to stop a trailer skid?

Releasing the brakes
Not using the hand brake
Recognizing the skid
Using the trailer hand brake to get traction back

8. If your vehicle has dummy couplers, why should you use them when the air lines are not connected to a trailer?

To prevent freezing of the washer liquid.
Because if you don't, you will never build system pressure.
To prevent overheating.
To prevent water and dirt from getting into the coupler and the air lines.

9. When parking a trailer without spring brakes, it is very important for safety that you use wheel chocks. Why?

if you don't use wheel chocks, supply air will be sent to the service line instead of going to charge the trailer air tanks.
The air could leak out of the trailer air tank, releasing its emergency brakes.
You may not notice a major leak in the service line until you try to put the brakes on.
None of the above.

10. What happens when the center of gravity of a truck moves higher up from the road?

The vehicle is more stable while turning.
The truck becomes easier to turn over.
It becomes much easier to downshift at the right rpm.
It is easier it is to turn around corners.

MS CDL COMBINATION PRACTICE TEST