Heavy Duty Trucking, December 2020

Fastener retainers can prevent nuts from backing completely off but they wont indicate a possible loss in clamping force if excess material between the wheel and the mounting face comes loose Periodic torque checks are still required precise machining and the tighter tolerances involved but it becomes a value equation for the fleet They are easier and less timeconsuming to install and they usually come with longer warranties As well when the technicians follow the installation instructions the bearing is pre tightened properly every time It takes away some of the technicians discretion in how the hub and bearings are installed Hicks cautioned that technicians may still need some training to help them identify a pre adjusted hub Theres risk of damage to the bearings and the bearing spacer if excessive torque is applied to the retaining nut during installation 2 CHECK WHEEL ENDS DURING PMS Bearing condition can be checked during regular preventive maintenance inspections by jacking up and safely supporting the wheel and rotating it while listening for noise Maye suggests placing a hand on the steering knuckle or brake chamber to check for vibration when the wheel is rotating Next check for movement or chucking by placing a pry bar under the tire and with one hand on top of the tire lift the wheel end and feel for movement between the hub and the spindle Make sure to grease the kingpin on steer axles before this test as kingpin wear can feel like wheel end chucking he says If excessive movement is found wheel end service is required or any facial tissue Kleenex thats actually a brand name associated with ConMet Consolidated Metco This technology takes bearing adjustment out of the hands of the commercial vehicle manufacturer and guarantees that equipment leaves the factory with wheel bearings optimally adjusted for miles of service with a minimum amount of required maintenance says Roger Maye ConMets national service manager With pre adjusted hub assemblies a precision machined hub combined with tight tolerance bearings and spacer provide a fixed dimensional distance between the inner and outer bearing Simply spinning on the axle fastener and torqueing exactly to the manufacturers specification sets the bearings properly every time without the need to verify end play with a dial indicator says Drew Coen Stemcos wheel end product manager Pre adjusted hubs are easier to install and eliminate the need for fleets and repair facilities to have multiple parts to build a complete wheel end Coen adds The pre assembly of the components and ease of install saves the mechanics time and eliminates wheel end installation mistakes that could lead to costly and or unsafe conditions as the vehicle is put back into service Bill Hicks SAF Hollands director of product planning says fleets are slowly shifting to pre adjusted hubs for the labor savings and the relative ease of installation Weve seen slow but steady growth in orders for pre adjusted hubs on our axles he says They cost more because of the more structions not installation guidelines There also are generic instructions such as Recommend Practice 618B from the American Trucking Associations Technology Maintenance Council This RP describes a ninestep installation and adjustment process depending on the type of wheel end assembly finishing up with the use of a dial indicator to verify correct adjustment But industry sources say that because its finicky and time consuming the final step is often left out despite being one of the most critical parts of the process Thats a recommendation for an ideal situation admits John Heffernan SKF key account manager Getting techs to use torque wenches was a huge step for the industry Use of dial indicators is growing and more fleets are adopting the practice but we still have a long way to go Jeremy Gough director of national fleet maintenance at Bison Transport one of the consistently safest fleets in North America has a second technician check the work before the truck or trailer is released from the shop A second set of eyes goes a long way to ensuring the job is done right the first time he says It takes a bit longer but its less timeconsuming than dealing with a failure One option is switching from conventional to pre adjusted hubs sometimes generically called pre set hubs although much like people call any clear tape Scotch tape Only calibrated electric or pneumatic torque wrenches should be used to tighten wheel fasteners Regular pneumatic wrenches are okay for running the nut onto the stud but thats all DECEMBER 2020 HDT 43 WWW TRUCKINGINFO COM PHOTOS JIM PARK