Title: Test the operation of the fifth-wheel locking device.
Course: Diesel Equipment Technology I (20107-I) > Section: Preventive Maintenance and Inspection: Servicing the Frame and Fifth Wheel

Testing should adhere to required pre-trip and post-trip CMV inspection regulations and include checking the

- sliding fifth-wheel locking mechanism and locking pins
- king pin locking jaws
- fifth-wheel release arm safety latch
- adjustments of the fifth wheel.

ASE 1: IV. Suspension and Steering: H. Frame and Coupling Devices (P-1)

Process/Skill Questions:

- When the connection of the tractor and trailer is complete, doing a tug test is all that is required before operating the equipment on the highway. Is this correct, or must something else be done?
- When performing a visual inspection of the fifth wheel after the connection is made, about an inch of airspace is visible between the fifth wheel and trailer mounting plate. What does this indicate, and what should be done?
- Why is it important to inspect the king pin and king pin mounting plate, before connection?
- When a driver’s pre-trip inspection is conducted, an unusual amount of slack is noted in the connection during the tug test. Should the vehicle be driven or inspected for problems by a technician?