The Fleet Business Authority
Issue link: http://heavydutytrucking.epubxp.com/i/236631
Tires&Wheels; and type of media makes a difference. "The media should be chosen for coating removal and paint preparation," he says. "You can short-cut the process by using larger, more aggressive media, but you run the risk of pitting the wheel or possibly peening thin cracks closed. Use too fine a media, and the process takes longer." IMI's 20/20 blaster can strip a wheel to the bare metal in about three minutes in most cases with coating thicknesses up to 15 millimeters. Previously powder-coated or e-coated wheels with very durable finishes can take longer. All the previous coating has to be removed, and the surface of the wheel should be rendered reasonably smooth and free of shot pitting. Pit- ting deeper than 3 to 3.5 millimeters could result in excessive coating thickness on critical areas of the wheel. Once the old coating and all the corrosion has been removed, the wheel is inspected once again for damage that may have been obscured by the paint.. Mark Fonte, marketing and sales manager for OE Truck Wheels at Not fit for service Corrosion and wear Cracks Cracks can appear in several locations around the wheel for different reasons, and may appear as cracked paint at first. When the paint is removed during refinishing, the cracks become obvious. Any visible cracking on any part of the wheel is not repairable. Take the wheel out of service. • Cracks running from bolt-hole to bolt-hole indicate loose cap nuts. Review wheel torquing procedures. • Cracks running from hand-hole to hand-hole, hand-hole to bolt-hole or hand-hole to rim indicate overloading. • Circumferential cracks at the back flange radius, bead seat or in the middle of the rim indicate overloading or overinflation. 52 HDT • JANUARY 2014 PHOTO BY JIM PARK A bright and freshly painted wheel isn't necessarily a safe wheel. Damaged or worn out wheels should not be put back into service, but sometimes it's hard to discern the actual physical condition of a wheel when it covered in rust, peeling paint, etc. Close inspections of the wheel while it's stripped of coating can reveal damage you might miss otherwise. Take the wheel out of service and look for possible causes. Irregularities on the mounting face of this wheel were likely caused by loose fasteners. The damaged surface will prevent proper clamp load from being applied evenly around the wheel. This wheel should be scrapped. Distortion Bent or distorted wheels should not be repaired and returned to service. Even minor distortions can cause problems such as air seepage, leading to low-pressure conditions and irregular tread wear. A complete inspection should include checking for excessive run-out using a dial indicator. • Rim base or flange distortion, or chorded or bent rim gutters, can indicate excessive or improper torque, mounting to the wrong type of hub or a previous run-flat condition. • Wheels with worn or distorted bolt-holes indicate loose cap nuts and improper torquing procedures. Wheels or rims with heavy rust, corrosion or severe pitting cannot be repaired. Remove them from service. • Burrs or raised metal edges or protrusions around the boltholes on some wheels may be filed off using a flat file. These can be considered for refinishing if the bolt-holes are not distorted. As truck parts go, wheels are among the less expensive. Does it make sense to invest technician time trying to repair a damaged wheel? "At less than $100 in many cases, you can quickly find yourself wasting money trying to put damaged wheels back in service," says Mark Fonte, marketing and sales manager for OE Truck Wheels at Maxion Wheel. "Repairing wheels raises safety concerns. TMC lists a series of out-of-service conditions for steel wheels. Fleets can costeffectively refinish a wheel and restore its appearance, but it won't fix damaged wheels. Repairing wheels usually isn't worth the trouble." — Sources: Technology & Maintenance Council RP 222C, Accuride's W4.000 Wheel Out-of-Service Guide www.truckinginfo.com