Quote:
Originally Posted by vrooooom
I was just watching brake servicing on M2 Competition. It says 30 Nm + 90 deg.... but if re-use 110 Nm. Made me think about these one-time-use bolts. Why can't we re-use these bolts on stiffener plates but for (IMO) even more critical areas like what's holding our brake calipers or wheels are just torque to 110 or 140 and not need replacing w/ a new one.
Just throwing it out here. 
Time: 17:13
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First off some people reuse bolts that are single use because they either:
1) didn't know they must be replaced because they don't have ISTA.
2) Don't want to spend the kind of crazy price for bmw bolts.
3) Don't care.
But either way bmw says the bolts are single use so if you want to do it right the bolts must be replaced.
Well I just looked at ISTA and they do specify that both front and rear bolts must be replaced whenever removing them. Real oem says they are also the exact same bolt so despite bmw not specifying that the front bolt must be yielded as they only give a torque spec, since they are the same as the rear caliper bolts which do need to be yielded and thus stretched we know these bolts will stretch when subjected to torques past 30 nm.
This means they MUST be replaced and you really shouldn't reuse a previously stretched bolt. Because a previously stretch bolt is now weaker and is susceptible to snapping. It will also not be able to apply the same clamping load after the material is stretched (a bolt is stretched to enable it to provide a more equal clamping load along its whole thread length and prevent it from vibrating loose, once stretched its elastic properties change and clamping loads won't be the same anymore) so that bolt really shouldn't be reused.
So imo
FaRKle! shouldn't have put a used bolt torque spec, he should have said new bolts are required...