Another tidbit.... I just found out ( by experiment) that the 10mm Schnorr washers available under the Porsche part number ( listed within this thread, M10 999.523.103.01)..is the 1 mm thick version ( "S" type)...that is typically used under non-rated strength hardware.
Same goes for "small" purchases made thru McMaster-Carr....these are all "S" spec, even if they aren't labelled.
Strange..... as the CV stuff should be metric proprty class 12.9.
However, Jim Sims addresses this as being proper in that one-side of the fastened pair ( either the moon washers or the face of the CV joint).. is comparatively "soft" and doesn't lend itself to beneficial use of high-grade washers.
Nonetheless...for those that want to go this way, there is another version of the Schnorr washer available. It is 1.5 mm thick for 10mm size...and more closely matches the pre-tensioning required of "rated" hardware like metric property class 8.8 and higher. These are Schnorr "VS" style..and are typically available only through Schnorr-USA (
AFAIK) , or through supply houses, but only in large purchase quantities ( 100-250 minimum, or somesuch).
I think the VS style may be way to go, if you need Schnorr washers for CV applications.
Final note... I looked at some of these same washers ("identical", actually, to the 10mm CV Schnorr washers) that are used under the socket head cap screws of the top/front suspension members ( shock tower area). Removing these, it was apparent that they were squished flat....so the spring component was lost. I would think that these become "one use" items and should be renewed . The teeth were flattened and deformed, too.
- Wil
( EDITED for add'l text).