Pretrip Inspection and Daily Maintenance Fatigue or cracking of welds, which must be repaired according to the manufacturer’s specifications. 21. If so equipped, inspect the 7-way trailer cable re- ceptacle(s) for good connections. Clean and grease the 7-way socket and plug regu- larly, especially in regions where magnesium chlo- ride or calcium chloride are used as road de-icers. These chemicals are highly corrosive to brass and copper, the base materials for the contact pins used in the 7-way receptacles. Clean the socket and plug with a plug brush and apply a moderate amount of dielectric grease to both the socket and plug pins.
See Group 54 of the Cargo Maintenance Manual for an approved dielectric grease. 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. 20.4 Lubricate the fifth wheel top plate and other grease points at least once a week and more often in severe service. 22. Inspect the front and rear suspension components, including the springs, shocks, and suspension brackets. Before connecting the fifth wheel to the trailer kingpin, always be sure that the fifth wheel plate is completely lubricated with chassis grease.
Check for broken spring leaves, loose U-bolts, cracks in the suspension brackets, and loose fas- teners in the spring hangers and shackles. Inspect the shock absorbers for loose fasteners and leaks. 20.5 Clean all foreign material from the fifth wheel top plate. Lubricate the top plate surface, pickup ramps, and mounting bracket pivot pins using a waterproof or multipurpose chassis lubricant. Lubricate the jam mecha- nism on all units except the Fontaine ® 5000 series fifth wheel. (Fontaine recommends that jaws and wedges remain dry to avoid accumulation of abrasive matter.) Tighten all loose fasteners and replace any compo- nent that is worn, cracked, or otherwise damaged.
WARNING Do not replace individual leaves of a damaged front or rear suspension leaf spring assembly; replace the complete spring assembly. Visible damage, 9.12