freightliner Columbia Driver Manual page 145

12. The load distribution on the front steering axle
and rear drive axle(s) will have a direct effect on
the steering control of the vehicle.
Determine the front and rear axle weights by
weighing the vehicle on scales designed for this
purpose.
The maximum axle weight ratings are given on
the Federal Motor Vehicle Safety Standard
(FMVSS) label or Canadian Motor Vehicle Safety
Standard (CMVSS) label attached to the left rear
door post of the tractor. The desired load on the
axle is no less than 80 percent of the maximum
axle weight rating, but in no instances should the
axle load exceed the maximum axle weight rat-
ing given on the FMVSS or CMVSS label.
WARNING
Do not overload any tractor axle by improperly
loading the trailer. This could cause erratic steer-
ing and loss of vehicle control, possibly resulting
in serious personal injury or death.
Unlocking the Fifth Wheel Lock
Mechanism
1. Apply the tractor parking brakes.
2.
Pull the trailer air supply valve to cut off the air
supply to the trailer.
WARNING
Do not use the trailer air supply for parking trail-
ers not equipped with spring parking brakes.
This applies the trailer service brakes only. As air
bleeds from the trailer brake system, brake appli-
cation is lost. This could allow the unattended
vehicle to roll away, possibly resulting in serious
personal injury or death.
3.
Chock the front and rear of the trailer tires to
prevent the trailer from moving.
4. Lower the trailer landing gear until the weight is
removed from the fifth wheel.
5. Disconnect the tractor-to-trailer air system lines
and electrical cable. Plug the air lines to prevent
dirt or foreign material from entering the lines.
Fifth Wheels and Trailer Couplings
Before attempting to lock or unlock the fifth
wheel lock mechanism of a sliding type fifth
wheel, the slide release pull handle, if so
equipped, and the slide locking wedges must be
in the locked position. This prevents the sliding
member from moving rapidly to the far forward or
rearward position, which could damage the fifth
wheel member or kingpin.
6. Release the kingpin locking mechanism by lifting
the safety latch and pulling the lock control
handle to the unlocked position. See
7. Slowly drive the tractor away from the trailer.
Fifth Wheel Slide Operation
1. Connect the trailer kingpin to the tractor fifth
wheel. For instructions, refer to Fontaine "Fifth
Wheel Locking Operation," in this chapter.
2. After positive lockup of the fifth wheel lock
mechanism has been accomplished, release the
slide using one of the following methods:
2.1
9/07/95
Fig. 10.18, Cab Control, Fifth Wheel Slide
2.2
CAUTION
For air-operated release models, set the
cab-operated control switch
UNLOCK.
For manual release models, lift the slide
release pull handle to disengage it from
the guide plate. Then, pull out the handle
(Fig. 10.19) until it is in the unlocked posi-
tion and can be positioned against the
Fig. 10.17.
(Fig. 10.18) to
f310489
10.14