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Old 04-09-2008, 03:12 PM   #24
Beastly Adventurer
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Joined: Feb 2002
Location: Austin, Texas, USA
Oddometer: 3,201
Originally Posted by Hair
Our friends at BMW have concerns about using anti-seize on torqued bolts. Their concern is that any lubricant that is applied could mess-up the torque values.

I guess that inner thread friction affects torque values.
We measure torque as an analog of fastener stretch. We want to stretch the fastener sufficiently to ensure a certain level of tightness of the fastened parts. Anything like thread friction increases the perceived tightness of the fastener without increasing the tightness of the joint. In other words, we want it all slick as snot so the torque wrench only measures stretch.

Originally Posted by emelgee
As far as I recall the BMW issue was related to rear wheel nuts...
The cone washers, actually. Any tapers, generally, go unlubed. I've seen folks split auto brake hubs...

And yeah, I can't imagine that the cam bridge bolts could be dry. They were certainly oily by the time I got'em out, and I'm sure I can't replace them with getting oil on'em. But it sure felt like galvanic stickiness tryin' to break'em free. Nuthin nuthin nuthin.. bang!

Anti-seize will prevent reoccurence.
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