Fontaine Fifth Wheel Coupling

sdp dm 17.02.003
  1. Chock the front and rear of the trailer tires to prevent the trailer from moving.
  2. If equipped with a standard fifth wheel , check the surface of the fifth wheel for a liberal coating of grease.
    If equipped with a no- or low-lube fifth wheel , inspect the conditions of the pads.
  3. Ensure the fifth wheel jaws are fully open and the lock control handle is fully extended as shown in Fig..

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

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

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

    1. Pull Handle

    2. Fifth Wheel

    Fig. 1, Fontaine Fifth Wheel Lock Handle Positions

  4. If equipped with a standard fifth wheel , inspect the trailer kingpin plate to verify it is large enough to completely cover the fifth wheel and is properly greased.
    If equipped with a no- or low-lube fifth wheel , ensure the leading edge of the trailer skid plate is free of sharp edges.
  5. Make sure the fifth wheel top plate is tilted so the ramps are as low as possible.
  6. Position the tractor so the kingpin is in a position to enter the throat of the fifth wheel as shown in Fig..

    Fig. 2,  Positioning the Tractor

    7. Warning: When coupling, always inflate the tractor suspension air bags prior to coupling.

    Inflating the tractor suspension air bags while positioned underneath the trailer may result in damage to and incorrect coupling of the fifth wheel, possibly resulting in serious personal injury or death.

    Notice: Attempting to couple at the wrong height may cause improper coupling, which could result in damage to the fifth wheel or kingpin.

  7. Adjust the trailer height if required.
    For a standard fifth wheel , the trailer should contact the fifth wheel at the top of the approach ramps as shown in Fig..
    For a no- or low-lube fifth wheel , the fifth wheel must slide freely under the trailer; the trailer should contact the fifth wheel at the pivot point shown in Fig.

    • Fifth wheel must lift trailer

    • Adjust trailer height

    • Ramps tilted down

    • 4 to 8 inches

    Fig. 3, Trailer Connection Point, Standard Fifth Wheel

    • Adjust trailer height

    • Ramps tilted down

    Fig. 4, Trailer Connection Point, Low-Lube Fifth Wheel

  8. With the fifth wheel opening aligned with the trailer kingpin, back the tractor slowly toward the trailer. To prevent the trailer from slamming into the kingpin, after sliding under the trailer, stop . Then resume backing up slowly until the fifth wheel locks.
  9. Apply the tractor parking brakes.

    10. Warning: A visual inspection is required by law.

    Some improper couplings can pass a pull test. Sound is not reliable.

    Get out of the cab and look.

    Incorrect coupling could cause the trailer to disconnect, possibly resulting in serious personal injury or death.

  10. Perform a coupling inspection.
    1. Verify there is no gap between the bottom of the trailer and the fifth wheel as shown in Fig.
    2. Make sure the jaw and wedge of the fifth wheel are locked in place behind the kingpin as shown in Fig..

      • Check that there is no gap between the trailer and fifth wheel.

      • Verify the kingpin is locked in the fifth wheel jaws.

      Fig. 5, Coupling Inspection View

    3. Check that the lock control handle is fully retracted as shown in Fig.; the gap between the back of the pull handle and the skirt of the fifth wheel should be less than one inch as shown in .

      • Make sure there is less than a one inch gap between the back of the pull hand and the fifth wheel skirt.

      1. Pull Handle

      2. Skirt of Fifth Wheel

      Fig. 6,  Fontaine Fifth Wheel Handle Retracted

    11. Warning: Incorrect fifth wheel locking could cause the trailer to disconnect, possibly resulting in serious personal injury or death.

  11. Release the tractor parking brakes.
    Test for kingpin lockup by slowly inching the tractor forward, pulling on the trailer against the chocks.
  12. After lockup is completed and verified, connect the tractor-to-trailer air system lines and the electrical cable to the trailer. Take care to prevent dirt or foreign material from entering the air system lines.

    13. Notice: Always make sure the connection hanger keeps the trailer air hoses and electrical cables positioned so that they do not rub on anything. Rubbing may wear through hoses or cables, resulting in air leaks, or exposed or broken wires, potentially affecting trailer brake or electrical systems.

  13. Charge the air brake system with air, checking that the air connections do not leak.
  14. Fully retract the landing gear legs and secure the crank handle.
  15. Remove the chocks.
Note:
Parent topic: Fifth Wheel Coupling
Document Number: 0000111051
Manual Publication Date: 2024-09-03
Topic Publication Date: 2024-05-02