Proper Wheel End Service

It’s all about knowing the components and RTB

In the past 15 years wheel ends have seen several significant changes. In addition to wheel ends with manually adjusted tapered roller bearings, there are now have PreSet or LMS hub assemblies and unitized hub assemblies. Along with changes to bearing types, there have been changes to seals, lubricants and spindle nut systems, all of which have brought with them new procedures for installation and service. To properly service a wheel end, it is critical that the components be accurately identified and then serviced according to the correct procedures.

To gain some insight into effective wheel end maintenance and service, Fleet Maintenance Magazine turned to Roger Maye, national service manager for Consolidated Metco (ConMet), a division of Amsted Industries. Headquartered in Vancouver, WA, ConMet is a manufacturer of lightweight components for the heavy duty transportation industry.

A recent recipient of the Technology & Maintenance Council (TMC)’s highest honor - the Silver Spark Plug Award, Maye has been with onMet since 1977, serving in a variety of positions, including quality assurance manager and performance engineer before becoming national service manager. Here is what he had to say:

In his speech at the Technology & Maintenance Council (TMC) Fall Meeting this past September, Bryan Lewis of Wal-Mart Transportation, winner of the 2007 and 2008 TMC National Technician Skills (SuperTech) competition, passed along some advice he received from a co-worker early in his career. That co-worker told Bryan that if he wanted to be a good technician he needed to learn to RTB - read the book.

For the last 6 years, I’ve had the opportunity to work with the wheel end work station at the SuperTech competition and at a good number of state and fleet technician competitions. I’ve noticed that the best contestants are the ones that make the best use the service information provided at the work station.

I now start each group with the same orientation speech. I tell the contestants that we want them to identify the task, obtain the proper work instructions and complete the task based on the work instructions. Just like Lewis learned early in his career, the service literature is the starting point for any job.

This advice could apply to each station in a skills competition, or each job a technician completes in the course of his normal work day. As a technician reads a repair order and prepares to service a vehicle, he must make a diagnosis based on information from the driver and what he sees when he inspects the vehicle. Once the diagnosis is made, he needs to obtain the service information and the parts necessary to complete the repair.

Since the early days of ball bearings, wheel ends have had three things in common. To perform well, they must: be properly adjusted; be sealed to keep the lubricant in and contaminants out; and contain a lubricant appropriate for the application.


A manually adjusted hub assembly uses tapered roller bearings that require adjustment by the technician when the hub is installed on to the vehicle. TMC Recommended Practice (RP) 618 provides a good work instruction for manual bearing adjustment. Manual bearing adjustment must include the use of a dial indicator to insure that the bearings are adjusted to have from 0.001- to 0.005-inch of end play.

Like hubs with manually adjusted wheel bearings, PreSet and LMS hub assemblies use tapered roller bearings. While these bearings function like the bearings used in manually adjusted wheel ends, they are what the industry refers to as “half stand” bearings. They are manufactured to a closer tolerance than the bearings used in manually adjusted bearing systems.

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