In a car, wherever something rotates, there are bearings, and the engine and transmission contain dozens of them. The term "wheel hub bearing"—a slightly confusing term—is a bit confusing. Do you know what it is? And how do we maintain it in daily use? Let's learn more with Xingjie.
A wheel hub bearing is a critical automotive component. It connects the tire, brake disc, and steering knuckle. Its primary function is to carry weight, bearing both axial and radial loads. It also provides precise guidance for the rotation of the wheel hub.
Parts continue to evolve, and wheel hub bearings are no exception to this trend, adapting to various machine applications. Wheel hub bearings are developed based on two other bearing types: tapered roller bearings and standard angular contact ball bearings. By integrating these two bearings into one, they offer advantages such as light weight, large load capacity, excellent assembly performance, compact structure, and the elimination of clearance adjustment and external hub seals. This, in turn, has led to their widespread use in automotive parts.
Wheel hub bearings play a vital role in keeping the vehicle moving, reducing friction during chassis operation. Routine maintenance is essential. A malfunctioning wheel hub bearing will most directly cause noise, heating, and other symptoms. The following steps describe the key steps for removing a wheel hub bearing for your reference.
1. Remove the decorative cover and dust cover from the wheel hub axle.
2. Remove the tire without damaging the threads of the tire bolts. If you have disc brakes, remove the brake and then use a tool to remove the locking ring or pin.
Removing the Wheel Hub Bearing
3. Use specialized tools to remove the wheel hub bearing.
4. Remove any old grease, clean it with detergent, and then dry it with a rag. Finally, wipe the bearing cavity clean with a cloth.
5. Inspect the wheel hub bearing and bearing race. If any cracks, fatigue spalling, or loose bearing rollers are detected, replace the bearing. If pitting is found on the bearing race, replace the bearing.
6. Check the fit between the bearing inner diameter and the shaft journal. The clearance should be no greater than 0.10mm. When measuring the shaft journal, measure at two locations perpendicular to the ground (these are the areas of greatest wear). If the clearance exceeds the specified service limit, replace the bearing to restore the clearance to normal. Do not deburr or pit the shaft journal to reduce the clearance.
7. Once all parts meet the requirements, place the greased inner shaft into the wheel hub.
8. When applying grease, pay attention to the amount of grease applied. Apply from one end of the bearing to the other until it emerges. However, avoid applying too much grease inside the bearing cavity.
9. Reinstall the wheel hub and outer shaft onto the shaft diameter. Manually tighten the shaft head adjusting nut, then tighten the adjusting nut to the specified torque using a shaft head wrench. After tightening the nut, rotate the wheel hub several times to check the bearing fit. This rotation also ensures that the bearing and race are properly seated. At this point, the bearing is properly tightened, and the wheel rotates freely with no perceptible axial play.
10. Finally, install the lock plate, retaining nut, tire, dust cover, and decorative cover, in order.
11. After adjusting the wheel hub bearings, drive a certain distance, stop, and check the wheel hub. Feel the wheel hub for temperature. If it is warm, the bearing is overtightened and should be readjusted, loosening the bearing appropriately.
