Fifth Wheel - Midland SIDE DUMP GRAVEL TRAILER Operator's Manual

5.2.3

FIFTH WHEEL

A fifth wheel system is used on the rear of the front
B train unit and on the towing tractor to secure the
kingpin and carry the weight of the attached trailer. It
must be maintained in good condition to perform as
intended.
Visually inspect the fifth wheel as part of the pre-
trip inspection to check for cracks, bends, chips or
distortions of the frame and upper plate.
NOTE
Use a high-pressure washer or steam
cleaner to remove all the grit and
grease from the fifth wheel assembly
prior to each weekly inspection. Apply
a fresh coat of grease to the fifth wheel
assembly prior to hooking-up the trailer.
Clean the assembly every 5,000 miles (8,000 km)
or weekly and annually to perform a thorough
inspection. Check the frame and upper plate for
cracks, bends, chips or distortions.
When the components are clean, check that the lock
closes completely around the kingpin.
To Adjust the lock:
1. Obtain a Holland kingpin lock tester and place in
the throat of the lock. Close the lock.
2. The jaws should be snug around the tester but
not binding.
3. Use the adjusting nut on the front edge of the
fifth wheel to set the clearance of the jaws.
4. Use a light oil to lubricate all moving parts prior
to returning to service.
48
Fig. 42 FIFTH WHEEL
Fig. 43 KINGPIN LOCK