What should shops inspect on fifth wheels to ensure safe and reliable operation? “During the shop’s inspection and maintenance of the fifth wheel, it is important to understand how the fifth wheel operates, and that all parts and adjustments are maintained to the manufacturer’s specifications,” says Rob Nissen, director field service at SAF-Holland Inc. “Proper lubrication and adjustments are critical to the performance of the fifth wheel.
“The kingpin and upper coupler of the trailer should be maintained to the proper dimensions of the kingpin, ensuring that they are within specifications and that any deflection or wear is within out of service criteria,” Nissen continues. “Also, each fifth wheel has its own characteristics so it is important that proper training procedures are reviewed with technicians to ensure the fifth wheel is being properly maintained.”
Routine periodic maintenance and lubrication recommendations for fifth wheels from SAF-Holland include lubricating locking mechanisms every three months or 30,000 miles and thoroughly cleaning the locking mechanism every six months or 60,000 miles. Proper lubrication procedures include removing old grease and debris from all fifth wheel-to-trailer contact surfaces and applying new water-resistant lithium-based grease.
Justin Burie in the warranty department at JOST International also recommends that a certified technician inspect fifth wheel assemblies every three months or 30,000 miles. “First, inspect the mounting,” he says, “and repair or replace any missing or damaged fasteners and broken components. Then inspect the bracket pin bolts and make sure the locking tabs properly secure the bolts in place.
“Also check for proper lock adjustment,” Burie adds. “A properly adjusted fifth wheel should allow the kingpin to pivot freely. The kingpin should not move back and forth in a locked fifth wheel.”
It’s important to perform all fifth wheel maintenance with the tractor uncoupled from the trailer, Burie notes. “Lubricate the kingpin lock using a hand pump grease gun through the grease zerk provided on the skirt of the fifth wheel and apply grease to the trailer contact surface as well as a light oil to all moving parts,” he says. “For sliding fifth wheels, spray diesel fuel on the slide path of the base plate.”
“Fifth wheel care starts with input from the driver,” says Aaron Puckett, director of national fleet sales at Fontaine Fifth Wheel. “A driver should always be vigilant regarding fifth wheel operation and should report any changes in fifth wheel operation to the maintenance department.
“During a vehicle’s regularly scheduled service, the technician should always inspect the fifth wheel to make sure that no components are bent, cracked or missing, and that all fasteners are secure,” Puckett continues. “Also during scheduled service, the technician should test the fifth wheel’s lock to make sure it closes properly. This should always be conducted with a test kingpin instead of a trailer to ensure consistency.”
(Click “Next page” to continue reading the story.)