Manual Uncoupling

sdp dm 17.03.001
  1. Slowly back the tractor tightly against the trailer to relieve pressure on the fifth wheel lock.
  2. Apply the tractor and trailer parking brakes.
  3. Chock the trailer rear wheels.
  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.
  6. Verify that both the yellow parking-brake and red trailer-air-supply knobs are out, the tractor and trailer parking brakes are set, and that the trailer is prepared for uncoupling.
  7. Release the kingpin locking mechanism following the instructions for each manufacturer below.
    1. Fontaine: Lift the safety latch and pull the lock control handle to the unlocked position as shown in Fig..

      • A.The base of the pull handle within 1 inch of the fifth wheel indicates the fifth wheel jaws are locked.

      • B.A gap of more than 1 inch between the pull handle and fifth wheel indicates the fifth wheel jaws are partially open.

      • C.A fully extended pull handle indicates the fifth wheel jaws are open.

      1. 1.Pull Handle

      2. 2.Fifth Wheel

      Fig. 1, Fontaine Fifth Wheel Lock Handle Positions

    2. Holland FW35/33: Pull out the release handle as shown in Fig..

      • A.Pull the release handle to open the lock.

      1. 1.Lock Open

      2. 2.Lock Closed

      Fig. 2, FW35 Holland Locks Open and Closed

    3. Holland FWAL: Slide the handle forward to move the front notch on the locking plate clear of the bracket.
      Pull the handle completely out.
      Slide the handle forward again to hook the rear notch on the locking plate onto the bracket as shown in 

      • Locking Plate Rear Notch

      Fig. 3, Unlocking a Holland FWAL

    4. Jost: Depending on the fifth wheel either:
      Lift the release handle up into the wide slot and then pull the handle out while moving it forward as shown in Fig. Then lock the handle into the open position on the notch provided.

      • Lift the release handle up into the wide slot.

      • Pull the handle out.

      • While pulling the handle out, move it forward.

      Fig. 4, Unlocking the Jost Fifth Wheel

      Or, in the event of a failure in an air release system, pull the handle directly out and hook it open on the notch as shown in Fig..

      • Pull the retractable handle out.

      • Hook the handle open using the notch.

      Fig. 5, Jost Release Handle Unlocked

  8. Release the tractor parking brake then drive forward slowly, allowing the trailer to slide down the fifth wheel and off the ramps.
Note:
Parent topic: Fifth Wheel Uncoupling
Document Number: 0000110762
Manual Publication Date: 2024-09-03
Topic Publication Date: 2024-05-02