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SECTION 8
8.1
KING PIN AND UPPER COUPLER
8.1.1
Check king pin wear on the 2” diameter. Replace if worn down 1/8” or more.
8.1.2
Check bottom flange of king pin for cracks or broken pieces. Replace if necessary.
8.2
INSPECTION CRITERIA
8.2.1
Check fasteners connecting upper coupler assembly to chassis rail on vans. Check welds
on members supporting fifth wheel plate. Replace missing fasteners and gouge out and
reweld visible cracks
8.2.2
Check for cracks around attachment points where radius arm connects to the coupler.
8.2.3
Check for abnormal wear at all moving parts.
8.2.4
Check for cracks around the top of the king pin where it was welded to the fifth wheel plate.
8.3
FIFTH WHEELS
Fifth wheels are usually mounted on the tractor and are the connecting link to the trailer. The
location on the tractor frame has to be determined by tractor wheel base, desired weight distribution,
tractor frame section, trailer loading, and landing gear clearance. For proper steering control and
weight distribution, the fifth wheel is located ahead of tractor axle or ahead of tractor bogie
centerline. Mount fifth wheel according to tractor manufacturer's recommendations. Do not use "U"
bolts to mount fifth wheel to tractor. The height must provide clearance between tires and the trailer
when loaded allowing for spring deflection and tire chains. Proper mountIng is necessary for the
safe operation of the product and the safety of others.
The locking plunger on Holland fifth wheels must be adjusted on new fifth wheels and periodically
with wear. There is an adjusting screw in the crotch of the ramps on the right side. Adjust so locking
plunger moves freely into position with full travel behind the hinged lock.
After connecting the trailer to fifth wheel, block wheels, or lock brakes on trailer and pull against king
pin to check for-complete locking.
8.3.1
FIFTH WHEEL MAINTENANCE
To maintain proper operation the following must be performed periodically:
1.
Lubricate all moving parts with Number 2 diesel oil or suitable lubricant.
2.
Check lock guard operation. Make sure lock guard is between jaws before coupling.
3.
Check for proper locking and unlocking with free moving plunger. If jaws do not open
and close properly, check for foreign matter between jaws and jaw guides. Foreign
matter will prevent complete opening and closing.
4.
Replace all cracked or missing parts.
5.
Lubricate top plate with wheel bearing grease periodically.
MUST BLOCK 5
TH
WHEEL FOR USE WITH END DUMPS – SEE SECTION 9.8.4
See Holland’s Kingpin Service Bulletin by clicking on the link.
LINK TO VENDOR FILE