Wheel lug nuts (bolts) not coming loose
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My mechanic told me a long time ago never put anti seize on any lugnuts, if you torx them to propper torx you will never have a problem coming off.Also never stand and or bounce on a breaker bar as you can bend or break the pressed in threads which is expensive to get repaired as axles have to be taken out etc.Buick 215 that is a good idear to put anti seize on the hub.
Last edited by ajmille; 04-18-2011 at 08:31 PM.
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if the 2' breaker bar isnt enough this is great advice. creating more leverage with a pipe extension.
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Your mechanic can say whatever he likes, and you can believe whatever you like. But when anti seize is properly applied (thin, light coat to the studs only) there is simply no downside. The torque of lug nuts creates friction on the shoulder of the bolt into the chamfer of the wheel. THAT is the major clamping force as well as what keeps the nut from coming loose, not the friction created on the stud threads from the torque (actually the preload. Torque isn't a measure of clamping force, just how difficult it is to turn something). There should not be any anti seize or anything else in that shoulder/chamfer area.
This is why it is critically important to use the proper lug nuts for the chamfer of your wheels. Ford had an issue with the "upgraded" wheels on the F150s and Expeditions in the late 90s that caused a recall: they had used the same lug nuts on all of the wheels across the trim levels, but the premium wheels were made with a different chamfer angle than the rest. This caused the lug nuts to work themselves loose over the course of several thousand miles. No amount of tightening would change this, because the friction interface was simply too small to do the job. It didn't matter that the threads on the studs were in the same amount of contact as with the proper lug nuts - it's all about the shoulder/chamfer interface.
The only thing to consider when using anti seize on anything is that when you bring it to the same torque spec as if it were dry, your are increasing the clamping preload by probably 50%. This is the same as if it were lightly oiled. On the lug nuts and studs on these trucks especially, this is not even close to the clamping force you would need to get stud yield (stretching far enough to break or at least not return to size when unloaded).
It's also well known to actual engineers that lubrication on properly mated and torqued fasteners does NOT contribute to loosening. If you are counting on cruddy threads and "turning it until it squeaks", you're doing it wrong. In fact, you are much more likely to experience a failure with a fastener when putting it on dry than you are lubricated for a very simple reason: heat. The more times and to the greater extent that you heat a fastener, the closer it is to failure. And, believe it or not, when you're torquing dry and especially dirty things to 140 NM they can get very hot very fast. Not all over, but where it counts: on the thread faces.
The mechanics of how these fasteners work is "intro to mechanical engineering 101" type of knowledge, so its easily verifiable should anyone care to. There is an awful lot of ignorance about fasteners in the automotive repair and hobbyist arenas. I don't expect to change anyone's opinion on the topic with what I've posted, but if you'd like to try to tell me that I'm incorrect, as least come up with a considered response as I have, not "my mechanic told me so" or "some manual or web site (that hasn't properly researched the issue either) said it."
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bcolins
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05-13-2011 01:31 AM