How to Adjust the Fifth Wheel Play on a Tractor?

[DelHeidi]

Park the vehicle unloaded on a level surface, engage the trailer parking brake, and loosen the lock nut on the fifth wheel adjustment bolt. Turn the adjustment screw counterclockwise until it becomes difficult to pull the fifth wheel handle outward. Rotate the adjustment screw clockwise one full turn, then tighten the lock nut to eliminate the play.

[BraxtonLynn]

I've been driving trucks for over a decade and know all about adjusting fifth wheel clearance. Park on level ground, set the parking brake, loosen the lock nut with a wrench, and use calipers to measure the current gap – generally 3-5mm is ideal. Too much clearance causes rattling, while too little makes coupling/uncoupling difficult. Adjust both sides equally when turning the adjusting screw, and always tighten the lock nut before testing with a trailer. I check it before every long-haul trip and grease the moving parts – this extends the kingpin's lifespan. Incorrect clearance not only wastes fuel but can cause hidden frame damage during emergency braking.

[LaWalter]

Our fleet has strict operating procedures. Before adjustment, it is essential to confirm the stability of the tow hitch support legs and use a level to check if the frame is balanced. Recommended tools include a torque wrench paired with a vernier caliper. After loosening the fixing bolts, rotate the adjustment gear disc, measuring every 45-degree turn. The gap standard for new vehicle models is typically 4±0.5 mm, while older vehicles can be relaxed to 6 mm. Special attention should be paid to inspecting the wear of spring bushings—replacements are mandatory if wear exceeds 3 mm. After adjustment, conduct a towing test: drive with an unloaded trailer at 20 km/h and perform three emergency stops to ensure no abnormal shaking occurs.

[VonCorey]

I just learned how to adjust this last week. The master taught me to first detach the trailer and raise the front support legs. Use a 19mm wrench to loosen the four fixing nuts, but don't remove them completely. Check the position of the adjustment hole, turn clockwise to reduce the gap, and measure with a feeler gauge after every half turn. Tighten the nuts immediately after adjustment, with torque reaching 120 Nm. Once I forgot to tighten them, and the nuts came loose on the road, almost causing an accident. Now I remember to mark with a paint pen after each adjustment, so I can check for loosening next time.