Fifth Wheel Slide Operation
- Connect the trailer kingpin to the tractor fifth wheel. For instructions, refer to Fontaine "Fifth Wheel Locking Operation," in this chapter.
- After positive lockup of the fifth wheel lock mechanism
has been accomplished, release the slide using one of the following
methods:
- For air-operated models, set the cab-operated control
switch (see Fig.) to UNLOCK.
Fig. 1, Cab Control, Fifth Wheel Slide
- For manual release models, lift the slide release pull
handle to disengage it from the guide plate. Then, pull out the handle
(see Fig.) until
it is in the unlocked position and can be positioned against the guide
plate to hold it out. The slide release pull handle will stay in the
unlocked position until it is manually disengaged from the guide plate.
Fig. 2, Fontaine Sliding Fifth Wheel Manual Release
- For air-operated models, set the cab-operated control
switch (see Fig.) to UNLOCK.
- Lower the trailer landing gear just enough to remove the weight from the tractor.
- Pull the trailer air supply valve to cut off the air supply to the trailer.
- Chock the front and rear of the trailer tires to prevent the trailer from moving.
- Slowly move the tractor forward or backward until the fifth
wheel is in the desired location.
- Apply the tractor parking brakes.
- Lock the sliding member into position using one of the
following methods:
- For air-operated release models, set the cab-operated slide control switch to LOCK. Visually inspect the locking wedges to make sure that they are fully inserted in the slide rail slots.
- For manual release models, disengage the slide release pull handle from the guide plate. The slide release pull handle is spring-loaded in the locked position and will seek the locked position when disengaged from the guide plate. The fifth wheel may have to be moved slightly to enable the locking wedges to fully enter the locked position. When the slide release pull handle returns to the fully locked position, visually and physically check the locking wedges to make sure they are fully inserted into the slots in the slide rails. Make sure the slide release pull handle is locked in position against the guide plate.
- The amount of 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 shown 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 rating given on the FMVSS or CMVSS label.
Warning: Adjust the fifth wheel slide correctly, and do not overload any tractor axle by incorrectly loading the trailer. Incorrect slide adjustment or improper axle loading could cause erratic steering and loss of vehicle control, possibly resulting in serious personal injury or death.
Warning: Do not use the trailer air supply for parking trailers not equipped with spring parking brakes. This applies the trailer service brakes only. As air bleeds from the trailer brake system, brake application is lost. This could allow the unattended vehicle to roll away, possibly resulting in serious personal injury or death.
Notice: After moving the fifth wheel to the desired position, be sure the trailer landing gear will not, at any time, come in contact with the tractor frame or other components. Make sure that the front of the trailer will not come in contact with the rear of the cab or with other components if they extend beyond the rear of the cab.
Note: The fifth wheel may have to be moved slightly to enable the locking wedges to enter the fully locked position.