3-2
F-1044-0719
OPERATING INSTRUCTIONS
Pre-Coupling of Semitrailer and
Tractor
1.
Slowly back the tractor/truck (towing vehicle) up to
the front end of the semitrailer so the kingpin of the
semitrailer is centered between the tractor fifth wheel
jaws. Stop the towing vehicle just inches ahead of the
semitrailer. Set tractor parking brake.
2.
Check the semitrailer king pin plate. It should be in a
horizontal position. The king pin plate should be the
same height, to slightly lower, than the latch area of
the fifth wheel plate of the towing vehicle. Drain all air
and moisture from the towing vehicle air brake
system following vehicle manufacturers instructions.
3.
Connect the service and emergency air hoses of the
towing vehicle to their respective gladhand on the
front of the semitrailer; red emergency line to the
gladhand with the “EMERGENCY” tag, and the blue
service line to the gladhand with the “SERVICE” tag.
Chock the semitrailer wheels before activating the
semitrailer air supply valve in the towing vehicle. Set
the parking brakes.
WARNING
4.
Check the air brake operations of the semitrailer as
follows:
a.
Apply brakes and inspect brake action on all
wheels for prompt application.
b.
Release brakes. All brakes should release
immediately. Air pressure should discharge
quickly from the relay emergency valve.
c.
Disconnect the emergency air line from the
semitrailer gladhand. Trailer brakes should
promptly set.
d.
Re-connect the emergency air line to the
semitrailer and activate the semitrailer air supply
valve. The semitrailer brakes should set.
Failure to chock semitrailer wheels could allow
unintended movement of the semitrailer resulting
in serious personal injury, death, or damage to
property in its path.
