Maintenance and Care of Heavy-Duty Vehicle Wheel Hub Bearings

Since vehicle bearings operate in a moving wheel environment and endure significant loads, they are highly susceptible to damage. Never underestimate their importance—improper installation, usage, lubrication, or maintenance can not only shorten their lifespan but also compromise safety. Below, we will provide a detailed guide on how to properly maintain and care for wheel hub bearings.

Heavy-duty vehicles typically use tapered roller bearings in their wheel hubs. During secondary chassis maintenance, all wheel hub bearings should be removed for servicing. The specific workflow is as follows:

1. Cleaning the Bearings

Wipe off the lithium-based grease from the surface of the disassembled bearings with a clean cloth. Then, thoroughly clean the bearings with diesel fuel or a dedicated bearing cleaner. Finally, wipe away any remaining diesel or cleaner with a cloth.

2. Inspecting the Bearings

Check the bearing cage for deformation and examine the rollers for signs of burning, blackening, grooves, or cracks. Rotate the bearings several times to listen for abnormal noises and assess whether they rotate smoothly without excessive looseness or resistance. Inspect the inner and outer bearing seats of the wheel hub for grooves or pitting, and check for looseness by manually rotating the bearing seat. Replace the entire bearing assembly if any issues such as a dislodged cage or grooves are found.

3. Lubricating the Bearings

Before lubrication, ensure there are no foreign objects (e.g., wire fragments) on the bearings. Apply lithium-based grease evenly to fill two-thirds of the bearing clearance—neither too much nor too little. Excessive grease may melt due to high heat from the wheel hub, while insufficient grease will fail to provide proper lubrication. Do not apply grease to the inner groove of the wheel hub, as this can impair brake drum cooling and reduce braking safety.

4. Installing the Bearings

Carefully install the bearings onto the axle using a dedicated bearing sleeve, applying even force to all parts. Never strike the bearing cage or rollers directly. When tightening the bearing lock nut, apply appropriate force—excessive force can damage the bearing and shorten its lifespan, while insufficient force will fail to secure it properly. After tightening, rotate the wheel hub several times to ensure smooth, unobstructed movement.

5. Replacing the Bearings

If replacement is necessary, use bearings of the original model (indicated on the bearing itself). When replacing, always change the bearing seat along with the bearing.

During maintenance inspections, it is common to find improper bearing servicing practices. Some mechanics skip disassembling and lubricating the wheel hub bearings during secondary chassis maintenance, simply reinstalling the hub as-is. Others remove the bearings but fail to clean them before reapplying grease, mixing old and new grease. These are all non-standard practices and should be avoided!

Given the harsh working conditions of bearings, the lubricating grease deteriorates over time, losing its protective and lubricating properties. If the grease is not replaced, the bearings will not receive adequate lubrication, drastically reducing their service life—the consequences of which are self-evident.

Proper maintenance is crucial—always follow standardized procedures to ensure safety and longevity!