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Fifth Wheel Inspection and Maintenance

rear view of fifth wheel hitch
All Things Runnion
Blog Posts
March 1, 2023

When the fifth wheel is even slightly hard to release, it’s time for maintenance!


Ideal Operation:
The trailer nose should make contact with the fifth wheel slightly behind the bracket pins, tipping the top plate flat during coupling. When dropping a trailer, crank the landing gear close to the ground, then dump the suspension air to reduce the weight on the fifth wheel before pulling away.


Warning Signs

  • If the fifth wheel is hard to release, it will be hard to hook
  • When grease thickens with colder temperatures, moving parts can bind, especially under the top plate
  • Sand, gravel, and cinders can build up with corrosive de-icing agents and old grease to restrict movement of the fifth wheel
  • Dented top plates can affect the jaws or the ability to lock them
  • Cracks in the grease can indicate loose pins or cracks in components
  • Loose pins on the top of the plate may indicate you need to replace the fifth wheel
  • Stuck slider locks may indicate corrosion
  • Missing or ineffective fasteners can render a truck out of service


Our 10-Step Fifth Wheel Maintenance

  1. Clean fifth wheel top plate, jaw, and legs
  2. Inspect top plate, looking for damage, missing parts and excessive wear. Check for dents and signs of grease seepage
  3. Check locking mechanism using a test pin to assure smooth operation
  4. Adjust locking mechanism
  5. Inspect bracket pins and legs, checking for cracks, damage, and signs of wear
  6. Inspect trailer bolster plate and kingpin for signs of deformity
  7. Lubricate jaw and locking mechanism
  8. Lubricate bracket pins and grease gun
  9. Lubricate top plate
  10. Check operation


Schedule your Fifth Wheel Maintenance with Runnion Equipment today!    1-800-824-6704