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Old 10-04-2017, 07:59 PM
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andrewwynn andrewwynn is offline
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Location: Racine, WI
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Quote:
Originally Posted by Scott ZHP View Post
I've seen this quoted a number of times. Just curious where you're getting this figure.

Grade 8 3/4 SAE is good for a minimum of 50,000lb tensile strength. That's more than enough to yank a wheel bearing,

I use a priceless app called iEngineer.



Screen shot of grade 8 3/4 bolt specs.

The shaft of a 3/4 bolt might yield at 50k but I'm very confident in the data in the app that I use having reliable sources.

Tensile strength of Gr 8 is 150ksi. That puts a theoretical strength of about 120,000# but the problem is the nut to bolt threads are what's holding things together. The problem isn't the shaft breaking it's the threads folding over.

33,570# is the clamp force of 3/4" Gr8 bolt. That's 100% rated. There is surely some safety margin but not 17,000# worth.

I do think that a Gr8 bolt 3/4 has a very good chance of pulling out the front bearing of the X5 but I would definitely heat up the carrier!

When I applied on the order of 30-33,000# of force in my case it laughed at me. When I heated the carrier to 250° F while pre-loaded to 15T it suddenly moved with a literal BANG.

That bearing is no sh%# stuck in there tight! Be prepared with some muscle to push it out!

Even with my 28T press I might heat the carrier to ease things along.
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