Fontaine

p4 mm 31.05

To maintain proper fifth wheel operation, always lubricate the fifth wheel after an inspection has been performed.

    Warning: Failure to properly lubricate the fifth wheel could result in a possible disengagement of the trailer from the tractor, which could result in personal injury or property damage.

    Important: Lubricate the fifth wheel:

    • After power washing, or steam cleaning.

    • If the vehicle operates in harsh conditions such as salt spray from road surfaces, or in extremely dusty environments.

    • After any service that requires removal of lubricant from the fifth wheel head or components.

  1. Tilt the top plate forward (the front of the fifth wheel is down) and apply grease to each bearing area through the zerk fittings located on each side of the top plate just to the front of the bracket pins. Continue to apply grease until it is coming out of the back of the bearing. It may be necessary to raise the rear of the fifth wheel with a pry bar to open up the pocket slightly and allow the grease to flow through. A substantial amount of grease may be required initially to fill the reservoir.
    Tilt the fifth wheel ramps down (the rear of the fifth wheel is down) and repeat the greasing procedure. Rock the top plate back and forth several times to spread the grease over the bearing surface.
  2. Inspect the trailer kingpin plate and top surface of the fifth wheel to make sure each is properly greased. A liberal coating of grease should be applied to the complete surfaces of both the trailer kingpin plate and the top surface of the fifth wheel.
  3. Note: Do not use a lube plate (high density polyethylene) on top of the fifth wheel or on the kingpin instead of grease without prior approval by Fontaine Fifth Wheel. The additional thickness of this material can prevent the proper operation of the fifth wheel and may cause a dangerous condition.

    Note: Fontaine suggests the use of a Moly based lubricant such as Mobilgrease XHP 320 or equivalent when applying lubricant to the locking jaw and wedge.

  4. Lubricate the fifth wheel prior to opening and closing it. Separate the jaw and wedge with a screwdriver, and grease the full length of their mating surfaces. Lubricate the top and bottom contact surfaces of the jaw and wedge. See Fig.. Open and close the fifth wheel several times to further distribute the grease.
    Lightly oil other moving parts in the fifth wheel.
    1. Pull Handle

    2. Jaw

    3. Wedge

    Fig. 1, Fontaine Fifth Wheel

  5. Apply grease to the top plate. Spread grease all over the mating surface of the top plate. Be sure the grease pockets built into the top plates are full of grease.
Note:
Document Number: 0000102784
Manual Publication Date: 2024-05-15
Topic Publication Date: 2025-04-05