Wheel bearing shims

[Christopher]

Sometimes the blue book instructions might as well be witten in Greek to make them more understandable. I'm trying to get my head around how to determine the correct thickness of shims when replacing the rear wheel bearings

The Blue books describe it thus http://www.e9-driven.com/Public/Library/BMW-E9-Manual/pages/en/33416010.html#refertoc

Can anyone explain this to me a bit more simply, or point me in the right direction to find some clearer instruction online ?

Many thanks

 

[Ed G]

What the manual indicates is that the spacer C must equal (A-B)-.1mm

The case the manual cites is (63.5-58.6)-.1 with the result=C or 4.8mm

You should only have to worry about this if the spacer, or A or B have worn, or been compromised. In other words, if no component dimensions have changed, just replace the bearings with new ones and reuse the same spacer.

Bearing ID, OD, and width variances, are held to such tight tolerances so as not to be significant in this equation when installing new bearings.

The C3 designation pertains to the internal clearance built into the bearings as manufactured. C3 clearance is a common industrial standard and are available from any industrial bearing distributor or auto parts store.

Inner wheel bearing- 6206 C3
Outer wheel bearing- 6208 C3

 

[Stevehose]

I couldn't understand this either so that's what I did. No ill effects thus far. A PITA job through and through.

You should only have to worry about this if the spacer, or A or B have worn, or been compromised. In other words, if no component dimensions have changed, just replace the bearings with new ones and reuse the same spacer.

 

[Christopher]

Thanks Ed, although i'm still having a little difficulty getting my head around the mathematics, what i can glean from this is that i can use my existing shims with the new bearings. Thanks for taking the time to explain that