Fifth Wheels throat of the locking mechanism. See Fig. 11.3 . Ad- just the trailer landing gear to give enough align- ment height so that the fifth wheel picks up the trailer on the fifth wheel ramps. could cause the trailer to disconnect, possibly re- sulting in serious personal injury or death. 7. After lockup is completed, connect the tractor-to- trailer air system lines and electrical cable to the trailer. Take care to prevent dirt or foreign material from entering the air lines. 4. With the fifth wheel lock opening aligned with the trailer kingpin, back the tractor slowly toward the trailer, making sure that the kingpin correctly enters the throat of the locking mechanism.
When the trailer is picked up by the fifth wheel, stop the trac- tor, then resume a slow backward motion until posi- tive lockup occurs. 8. Charge the air brake system with air. Make sure that the air connections do not leak. 9. Retract the trailer landing gear and secure the ratchet handle. 5. Apply the tractor parking brakes. 10. Remove the chocks from the trailer tires. 6. Make a visual check for proper kingpin lockup. Re- lease the tractor parking brakes. 11. The load distribution on the front steering axle and rear drive axle(s) will have a direct effect on the steering control of the vehicle. Test for kingpin lockup by pulling on the trailer against the chocks.
Check for correct maximum clearance between the lock halves. If more than 1/8-inch (3.2-mm) clearance exists between the lock halves, the lock must be adjusted. Refer to Group 31 of the Cargo Workshop Manual for ad- justment procedures. Determine the front and rear axle weights by weigh- ing the vehicle on scales designed for this purpose. The maximum axle weight ratings are shown on the Federal Motor Vehicle Safety Standard (FMVSS) label or Canadian Motor Vehicle Safety Standard (CMVSS) label attached to the left rear door post of the tractor.
The desired load on the axle is no less than 80 percent of the maximum axle weight rating, but in no instances should the axle load exceed the maximum axle weight rating given on the FMVSS or CMVSS label. WARNING Adjust the locks correctly to a maximum clearance of 1/8 inch (3 mm). Incorrect adjustment of the lock 11.3