Fifth Wheel Inspection and Maintenance
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
- Clean fifth wheel top plate, jaw, and legs
- Inspect top plate, looking for damage, missing parts and excessive wear. Check for dents and signs of grease seepage
- Check locking mechanism using a test pin to assure smooth operation
- Adjust locking mechanism
- Inspect bracket pins and legs, checking for cracks, damage, and signs of wear
- Inspect trailer bolster plate and kingpin for signs of deformity
- Lubricate jaw and locking mechanism
- Lubricate bracket pins and grease gun
- Lubricate top plate
- Check operation