Assembly problems with second generation hubs

Hubs with newer types of bearings, the so-called second generation hubs (Hub 2.1) are becoming more and more popular design solutions in vehicles. Concerns producing vehicles with such a solution are mainly the VW-Audi-Skoda and Ford-Mazda-Volvo groups.

The main advantage of such a solution is a consistent, modular design to increase hub life. However, the service life of this element largely depends on the correct one assembly. Second generation hubs available also in the BTA offer. Level analysis complaints from the last few months showed an increased complaint rate of some indices of this type of hubs. To find the source of the problem in detail we have analyzed the most common cases of complaints.

We made the analysis in cooperation with our laboratory, which helped us find the cause of the disturbing situation. The complained hubs were sorted into groups, according to the reasons for the notifications complaints, it is illustrated in the diagram below. The vast majority of reports concerned noisy bearing operation.

Our next step was checking what secrets the hub hides in middle. For this purpose, each hub was cut and subjected to further tests. The condition of the surface of the raceway, balls, lubricants and sealants.

The result of the analysis

As a result of the tests, it turned out that there were some inside the hubs very serious damage to the treadmill, such as: surface flaking, occurring in the pitch distances of the balls, which accompanied by internal corrosion and impurities in the lubricant.

The cause of such damage

The observed raceway dents are caused by impact loading during assembly. If during assembly, excessive force is applied to the hub flange, it will cause the balls to be deformed on the surface of the bearing raceway. Damage initially imperceptible, progresses during work. Already in the initial period operation, the damage to the raceway propagates and further flaking of the layer occurs top.

Treadmill after 6,000 km has greater flaking material. However, the treadmill after 10,000 km shows as exfoliation propagated. As a result of peeling material from the surface the treadmills break off fine pieces that come together with grease, they get through throughout the bearing space. In this way they lead to its progress damage.

With the progressing exfoliation of the raceway, the detached raceway particles, acting as abrasive particles lead to damage to the bearing seal. As a result, to moisture gets inside the bearing and external contaminants, definitively destroying the hub. Analogous examples and causes of damage are described in detail in widely available literature technical.

Conclusion after analysis

The analysis shows that the main cause of noisy work and damage to the hubs type HBU 2.1 there are assembly errors. So how do you prevent incorrect assembly? When assembling and disassembling the hub, be sure to use specialized ones tools – pullers – intended for this purpose. Their use makes it possible simple replacement of the hub without the risk of damaging it. Pullers designed for 2nd generation hubs are available in the Inter tool offer Cars S.A.