Fifth wheel test unit

Compatible with all 2" and 3,5" king pins.

Order No.: SKE008630000


The JOST fifth wheel test unit is an important aid for you: The locking mechanism of JOST fifth wheel couplings can be examined and, if necessary, readjusted quickly, easily and accurately. The fifth wheel test unit is suitable for all 2“ fifth wheel couplings as well as for 3 ½“ fifth wheel couplings when using a king pin adapter. (Order No.: KZ Adapter)*

Your advantage

  • Adjustment is straightforward and time-saving with no need to dismantle the fifth wheel coupling or trailer
  • Compact and robust
  • Simplifies the adjustment of king pin sensors on sensor fifth wheel couplings

    *  The king pin adapter has no ECE approval and is not suitable for use on public roads.

    Automatic lubricator

    All users of low-maintenance JOST couplings can save time and money by fitting an automatic lubricator because it will grease the fifth wheel lock jaw for up to six months.

    Due to the unavoidable dirt and corrosion that affect the top plate and king pin in every use, we recommend the following:
    • Clean at regular intervals
    • Apply a thin film of grease to the coupling plate
    • Grease the fifth wheel coupling pin and lock jaw
    • Use an automatic lubricator

    This servicing work must be completed at least every 50,000 km or every six months, in tough operating conditions every 25,000 km. The automatic lubricator supplies the lock jaw with the required grease through the connection at the edge of the fifth wheel coupling plate. Please also see the mounting and operating instructions for the automatic lubricator.


    Order No.: SK 3108-012

    Wear limit gauges 2“ and 3 ½“

    The JOST wear limit gauge may be a valuable tool for you. The lock on JOST fifth wheel couplings is adjusted at the factory to provide initial horizontal play of approx. 0.3 mm in the direction of travel with a new king pin.

    This longitudinal play may increase to 2 mm as a result of wear on the lock jaw or wearing ring. JOST fifth wheel couplings offer stageless adjustment to compensate for wear in the coupling lock. Only when this adjustment distance has been exhausted the fifth wheel coupling has to be repaired. The JOST wear limit gauge makes it possible to determine whether the lock on a 2" or 3½" JOST fifth wheel coupling or a 2" or 3½" king pin has reached or exceeded the permitted wearing limit while the coupling is disconnected and closed.

    Your advantage

    • A wear gauge for everything – for the fifth wheel coupling locking mechanism as well as for the king pin
    • Simplifies the wear and tear examination and saves time
    • Light and easy to handle
    • Calibratable gauge

    Item: J 1027 for 2"

    Item: J 1044 for 3 ½"


    Note: Further instructions for testing when coupled are given in the JOST repair instructions for fifth wheel couplings.

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