The Fleet Business Authority
Issue link: http://heavydutytrucking.epubxp.com/i/307131
should include close looks at the impact guard for evidence of cracks, bends or corrosion in its various members, and the welds and fasteners holding them together. The RIG also must be prop- erly aligned to the trailer's structure. Fenton emphasized that rear impact guards differ among trailer builders and most parts are unique to the manufac- turer, as are floor, sill and crossmember designs, which together account for 20% of a trailer's rear. Those parts must be acquired and used in any repairs. Time to look at fifth wheels It was a long winter in much of the country, and a delayed spring might have set back your preventive maintenance efforts. Several months' worth of sand, gravel, aggressive salts and road debris are now bound up in all the old grease caked onto your fifth wheel. Aside from being damagingly abrasive, all that crud can interfere with the lock mechanism. If a driver writes up a fifth wheel as hard to release, it's a good indication that it's also hard to hook. It's time to clean out the mechanism so you can do a proper inspection. Exact requirements for visual and mechanical inspection vary by manufacturer, but essentially you're looking for damage to the top plate, slack in the jaws, proper function of the jaws and the condition of the release handle. While adjustment procedures vary across brands and models, the allowable amount of slack does not. Roadside inspectors will sideline a truck with any more than half an inch of fore/aft move- ment between the top plate and the trailer, while the manufacturers recom- mend about 1/16-inch freeplay around the kingpin. There's some latitude there, but excessive slack is uncomfortable for the driver and will eventually wear the throat of the fifth wheel. Corrosion could become an issue with bare metal springs, so inspect them carefully and replace as necessary. There's no definition for wear on the springs, and as long as they are cycling properly, the springs are doing their job. Pull handles can be damaged or bent easily, and in some cases, a bent handle could impede the locking mechanism. Check the fasteners or the slider mechanism. If 20% or more of the fasteners are missing or ineffective, the truck can be placed out of service. Non- functioning sliders can be a huge source of frustration for drivers. Therefore, cycle the slider periodically to keep it from seizing. Properly lubricated fifth wheel top plates will retain peak performance for a long time, but grease is often applied incorrectly – usually too much. When the fifth wheel has been cleaned of old grease, apply a small bead of grease evenly in a back-and-forth motion. Ap- ply a heavier coat to the rear two-thirds of the fifth wheel; the grease will be pushed forward when hooking up to a trailer. Too much grease is wasteful and messy, and it does you no good stuck to axle housing and brake pots. While different types of greases or oils can be used, greases formulated specifically for fifth wheels provide the best lubrication. The proper thick- ness is crucial, as thin greases will wear away quickly during wet conditions and excessively thick grease may cause clumping – especially in the cold. When greasing the bracket bear- ings – if they require grease; some do not – use a pry bar to lift the top plate slightly off the bearing, and rock the fifth wheel back and forth while apply- ing grease. Some lubrication may be required on the underside, such as the locking mechanism, the cam track, or the pivots on the release handle. Use a light oil here. No-lube and low-lube fifth wheels may have grease fittings on the underside to ease lubrication of the lock mechanism and to prevent excess grease from accu- mulating on the mating surface. ■ 70 HDT • MAY 2014 www.truckinginfo.com Trailers www.truckin g info.com Read more on trailers each week from Senior Editor Tom Berg in his Trailer Talk blog at www.truckinginfo.com/ trailer-talk It's difficult to find a damaged rear impact guard because owners and drivers know they must be fixed before going on the road. Surface rust and dirt shouldn't result in a citation, but deeper corrosion and bends might. Every trailer builder's guard is different, so parts from individual manufacturers must be used in repairs. PHOTOS BY TOM BERG t r a i l e r s _ m a y . i n d d 7 0 trailers_may.indd 70 4 / 2 9 / 1 4 4 : 1 9 P M 4/29/14 4:19 PM