Fifth Wheel Slide Operation

cen dm 10.01.004
  1. Chock the front and rear of the trailer tires to prevent the trailer from moving.
  2. Connect the trailer kingpin to the tractor fifth wheel. For instructions, refer to "Fifth Wheel Locking Operation," in this chapter.
  3. After positive lockup of the fifth wheel lock mechanism has been accomplished, release the slide using one of the following methods:
    1. For air-operated models, set the cab-operated control switch (see Fig.) to UNLOCK.

      Fig. 1, Cab Control, Fifth Wheel Slide

    2. For manually-operated models, raise the safety latch and pull the slide operating rod (see Fig.) outward until the shoulder is outside of the operating rod support, then lower the operating rod as far as it will go.
      1. Baseplate

      2. Bolted Stop

      3. Baseplate Rail

      4. Fifth Wheel Mount

      5. Slider Saddle Plate

      6. Safety Latch

      7. Operating Rod

      8. Operating Lever

      Fig. 2, Taperloc Slide, Manually-Operated Release

  4. Lower the trailer landing gear just enough to remove the weight from the tractor.
  5. Pull the trailer air supply valve to cut off the air supply to the trailer.
  6. 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.

  7. Slowly move the tractor forward or backward until the fifth wheel is in the desired location.
  8. Apply the tractor parking brakes.
  9. 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.

    Note: The fifth wheel may have to be moved slightly to enable the locking plungers to enter the fully locked position.

  10. Lock the sliding member into position using one of the following methods:
    For air-operated models: Set the cab-operated control switch to LOCK. Visually inspect the lockpins to make sure they have seated in the baseplate rail holes.
    For manually-operated models: Raise the operating rod so that it is free to move inward. Make sure that the lockpins have seated in the baseplate rail holes and the operating rod moves into the locked position. Also, the safety latch must drop downward so that it holds the operating rod in the locked position.
  11. 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.

Note:
Document Number: 0000118708
Manual Publication Date: 2024-05-13
Topic Publication Date: 2024-06-06