Fifth Wheels WARNING Keep the fifth wheel plate lubricated to prevent binding between the tractor and trailer. A binding fifth wheel could cause erratic steering and loss of vehicle control, possibly resulting in serious per- sonal injury or death. 2 A 3. Position the tractor so that the fifth wheel lock opening is in line (both vertically and horizontally) with the trailer kingpin. The kingpin should be in a position to enter the throat of the locking mecha- nism, as shown in Fig. 11.5 . Adjust the trailer land- ing gear to give enough alignment height for posi- tive kingpin lockup. 1 2 4.
With the fifth wheel lock opening aligned with the trailer kingpin, back the tractor slowly toward the trailer, making sure that the kingpin enters the throat of the locking mechanism. Continue the backward motion until positive lockup occurs. B 1 12/05/94 f310265a NOTE: Make sure the safety latch is down when the control handle is locked. 5. Apply the tractor parking brakes. 6. Make a visual and physical check for positive king- pin lockup. When lockup has occurred, the fifth wheel control handle will have moved to the locked position. Make sure that the safety latch is down over the lock control handle. See Fig. 11.6 . This will hold the control handle in the locked position. 7.
Release the tractor parking brakes. Test for kingpin lockup by pulling on the trailer against the chocks. A. Unlocked B. Locked 1. Lock Control Handle 2. Safety Latch Fig. 11.6, Fontaine Fifth Wheel, Locking and Unlocking 11.8