[CobraCooter]

I am a mechanical designer of heavy industrial machinery. I think the most important thing that is being overlooked here is the critical necessity of properly torqing fasteners that are heavily loaded.

Gr. 8 fasteners and higher design properties are achieved only when they have been torqued or preloaded to the specified levels. Gr. 8 hardware does not perform and may experience premature or outright catastrophic failure if un torqued.

As Gr. 5 hardware has a much lower yield to ultimate ratio than gr.8 it is more forgiving and is used for general assembly. And I hate to be a bubble buster here but if the components in our cars were really under such heavy loads and subject to very high service factors then there would not be a fastener under 1/2-13 and 3/4, 7/8, and larger would be the norm.

Car companies are not in the business of putting peoples lives in danger and try their best to get a vehicle past the warranty stage.

My two sense anyways.

Mark