Spindle/hub parts question...
 

In the build up of the wheel end there is an oring (#28 on parts figure 999 701 084 50) that fits over the spindle between the strut and the spacer (#29 901 341 623 00).

What is the purose of this oring? Just keeping water/moisture from seeping under the spacer and rusting ring to spindle etc.?

That's a good question..

The only answer I have is that someone far wiser than me figured out it should be there. :)

Of course, these cars are so stoutly engineered that apparently they can run without that spacer at all. ;) ...for a while at least.

Its a grease seal.

It keeps hot, liquified grease inside the hub when the whole assembly is at operating temperatures and off the brake rotors.

Ahh good answer. Apparently I ran for the past few years on a hub with no spacer, much less no rubber seal! The bearing was beyond shot, but I'm surprised it didn't seize up..

Thanks Steve@Rennsport... SmileWavy that makes sense.

I guess it might also keep water out but likely the hot grease seepage would be a more frequent and potentially disastrous problem if it happened while running hard and you lost significant braking.