Premature bearing failure will impact a fleet’s efficiency with serious performance, safety and budgetary implications. Proper wheel bearing adjustment is a key factor for optimal bearing life. To reduce premature bearing failure in heavy duty wheel-end applications, the ideal bearing end-play setting should be between 0.001” and 0.005”.

The industry standard procedure TMC RP618, was developed for heavy duty wheel bearing adjustment to eliminate guesswork and ensure the ideal combination of reliability and safety. This procedure allows for a slight amount of end-play. This end-play should be measured with a dial indicator and verified by the technician at the time of installation. It is recommended that the technician record this end-play measurement on the work order for future reference.
 

Tight, But Not Too Tight: The Consequences of Improper Wheel Bearing Adjustment

 

TOO TIGHT (Preload)

If set too tight, it will create excess preload. This will cause the bearing to run hot and it will compromise lubrication. Eventually, this will lead to flaking at the large end of the rollers.
 
 

TOO LOOSE (End-Play)

If set too loose, it will create excess play and vibration in the system. This can lead to a multitude of issues including wheel wobble, seal leakage, ABS/braking problems and more. Eventually, a loose setting will cause flaking at the small end of the rollers/races and lead to failure. If failure becomes severe enough, it could lead to the wheel coming off!
 
 
Note: Always refer to TMC procedures “RP618 – Wheel Bearing Adjustment” and “RP622 – Wheel Seal and Bearing Removal, Installation and Maintenance” when servicing wheel bearings.