Fontaine
®
Fifth Wheel Handbook
14
3. Proper tractor/trailer alignment is critical to
obtain a secure coupling and to avoid equipment
damage.
Set the trailer brakes and raise the trailer to the
proper height by extending the landing legs. If
the trailer is positioned too high, the kingpin
may jump the fifth wheel throat and locking
mechanism altogether. Resulting damage may
include: scoring the fifth wheel, bending the
handle thus preventing the fifth wheel from
properly locking to the kingpin, bending the
kingpin, and other significant damage to the
tractor or trailer.
Coupling should not be attempted if the trailer
is too low. Costly damage may be incurred to
the trailer, the kingpin, the kingpin plate, the fifth
wheel, tractor drivetrain and truck frame.
4. To couple the fifth wheel to the kingpin, be sure
the fifth wheel is positioned so that it tilts down
at the rear and is resting on the stops.
Align the kingpin with the throat of the fifth
wheel and ease the tractor toward the trailer.
The trailer should strike the fifth wheel just at
the top of the approach ramps. The fifth wheel
will level with the kingpin plate and the kingpin
should slide into the fifth wheel throat.
Coupling is complete when the fifth wheel
locking mechanism snaps closed behind the
kingpin and the handle clip is properly installed
by the driver (See Figure H next page).
Verify secure coupling with a “tug test
,” by
easing the tractor forward to feel resistance of
the load. If the coupling feels secure, visually
inspect the fifth wheel.
The jaw and lockbar
(wedge) must be locked in place behind the
kingpin and the pull handle must be fully
retracted and secured in place using the
handle clip
(See Figure H next page).
