Practice question

Why must the fifth wheel be properly lubricated?

  1. To prevent the kingpin from corroding
  2. To improve fuel economy
  3. To prevent the air lines from leaking
  4. To allow the trailer to pivot on the fifth wheel without binding or wearing

Answer: D — To allow the trailer to pivot on the fifth wheel without binding or wearing

The correct answer is shown above. Try the full quiz for additional practice.

Practice more: Washington CDL Combination Practice Questions - Washington CDL Combination Vehicles Test Exam →