On cars with intermediate shafts (IRS, recognizable as driveshafts with homokinets), a rubber O-ring is located between the bearing housing of the rear axle and the bearing cover, and it is mounted around the bearing.
This O-ring prevents moisture from reaching the bearings. Many people think this is to stop grease, this is a misconception, this is what the retaining rings are for.
Many Volkswagens that have had their bearings replaced are missing this rubber ring, as they are not included in many bearing sets. Our bearing sets include them, so you don't need to buy them separately. Only if they are missing or if you have only removed the bearing cover is it advisable to replace them and not to put them back.
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