Wheel end seal leakage, and the subsequent costs of seal replacement, wheel bearing failure and brake damage, costs America’s trucking industry hundreds of millions of dollars a year in downtime, lost mileage revenue, wasted labor resources, and even lost customers.
This is a big problem, but not a hopeless problem as indicated by the following information from industry-wide sources and surveys:

• As much as 90% of premature seal failures are due to improper installation.
• Selecting the proper seal for the job is the first step in achieving wheel-end longevity.
• The incidence of seal failure traceable to compatibility issues with the new wheel lubricants is increasing rapidly.
• In all cases where improved installation training procedures were put into effect, warranty claims and the rate of premature seal failure decreased dramatically.

Chicago Rawhide’s Wheel End Trouble Free Operation Program – TFO® – has been developed to improve wheel end service life by first selecting the proper seal for the application, then by reducing premature seal and bearing failures. Ultimately, the bottom line is greatly improved by minimizing downtime and the high costs associated with wasteful maintenance practices.

     How does TFO work? Wheel End Trouble-Free Operation – TFO – is a systems approach where high product quality is just the baseline. As primary manufacturers with a singular focus, SKF and Chicago Rawhide are both leaders in their respective technologies of rolling bearings and elastomeric seals. But the TFO® program is much more than just products.

     The TFO program extends from products into the valuable realm of critical support services such as seal selection and evaluation, maintenance procedure recommendations, and the importance of training.

     The Wheel End TFO Program is designed to meet the specific needs of the truck fleets’ operation. Basically, the steps involved with Chicago Rawhide’s TFO program include the following:

• A TFO survey conducted by a CR sales representative to evaluate the fleet’s current wheel end maintenance program, procedures, and personnel practices.
• A comprehensive recommendation from CR based on the analysis of the TFO survey and estimates of the potential cost savings to the fleet.
• Implementation of the recommended TFO program at the fleet maintenance level.

The TFO Program uses a comprehensive survey to identify aspects of the wheel end maintenance operation where changes can be made which will improve the operation and in turn, enhance the bottom line. All aspects of the maintenance operation are covered in the comprehensive Wheel End TFO Program.
Seal Selection

Just as the equipment needs of long haul commercial fleets vary from those of heavy-duty construction fleets , so does the matchup of the right seal for the driving environment. A “good” seal can fail prematurely if used in the wrong application.

     Chicago Rawhide’s concept of “Different Seals for Different Wheels” recognizes the need for more than one seal for every purpose. The TFO Program analyses seal matchup to the fleet’s needs and recommends the optimum seal selection for your operation.
Different commercial fleets include:

• Over-the-Road
• Refuse Handling/ Sanitation Fleets
• Multiple Use Rental
• Municipal Bus Fleets
• Previously Owned Equipment
• Mining and Logging Fleets
• Trailer Fleets
• School Bus Fleets

Failure Analysis

A failed seal carries telltale signs which provide clues to the reasons behind its premature failure. Understanding these signs is the first step in preventing such failures to repeat.

     Over the years, Chicago Rawhide has examined thousands of damaged seals (from all manufacturers) and has analyzed the major causes of the damage. This knowledge has been distilled into our documentation and available within TFO documentation.
Also available is a comprehensive lubricant analysis which helps pinpoint various causes of the failure. Part of the TFO Program includes inspection and analysis of the fleet’s seal failures and a recommendation of steps needed to avoid similar failures in the future.
Below are the key failure modes for Scotseal® Classic Scotseal® Longlife. They will account for the majority of the premature seal failures:

Improper Installation

• Wrong tool or no tool used
• Cocked installation
• Lubricant contamination
• Metal Flakes
• Dirt or Water
• Mixing of lube types
• Improper bearing adjustment
• Seal spinning on spindle
• Damaged spindle
• Hub Imperfections
• Installed over a wear ring

For Scotseal® Plus, the most likely failure modes result from these common errors:

• Improper installation
• O.D. and /or I.D. not lubed
• Lube contamination as listed above
• Spindle not fully prepped
• Lubricants

The new synthetic lubricants hold promise of longer service life. However, careful management is essential, as a mismatch or mixing of lubricants and seals can have exactly the opposite effect-incompatible reaction between seal and lubricant and subsequent premature seal failure. The lube service interval must also not be ignored –doing so is putting the wheel end at risk.

     Chicago Rawhide’s R & D facilities are recognized as the finest in the industry. Lubricant tests are conducted continuously at these facilities on synthetic lubricants and their effect on elastomerics as used in wheel end seals. Lubricant compatibility was a major factor in the development of Chicago Rawhide’s new Scotseal Longlife line of seals. The correct matchup of seals and lubricants to the fleet’s needs is a major part of the TFO recommendation.
Tooling

Tools for removal and installation of wheel end seals are as critical to seal performance as they are to other tooling issues-imagine installing new pistons with a ball peen hammer!! Related tools such as wheel dollies and a properly calibrated torque wrench also play a role in the correct or incorrect installation process.

     Chicago Rawhide’s specialized tooling is designed for errorless, damage-free removal and installation of seals, with procedures that are easily understood by all fleet personnel. These tools, and the training on how to use them properly, are part of the TFO Program’s implementation process.
Training

Professional training of the fleet technician is the ‘silver bullet” to improved maintenance efficiency and the reduction of premature seal and bearing failure.

     To put training in its proper perspective, as much as 90% of all wheel end seal failures area results of improper installation.

     The TFO Program puts appropriate emphasis on training, with the goal of issuing “Certificates of Recognition” to participating fleet shop maintenance personnel. TFO training is conducted by highly knowledgeable, experienced Chicago Rawhide personnel, with hands-on learning, tooling demonstrations, videos and User Manuals. Education on the importance of wheel end systems and their critical role in the safety and productivity of the vehicle is an important part of the TFO program implementation.