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Discussion Starter · #1 ·
Bentley gives the following torque specs for the Front Subframe bolts:

8.8 grade - 77 Nm (57 ft lbs)
10.9 grade - 110 Nm (81 ft lbs)
12.9 grade 105 Nm (77 ft lbs)

I have one part number for the bolts from realoem and I don't have any choice when I buy from a vendor. So how do I know what the right torque spec is?
 

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The front subframe is held by 4 identical bolts. Impact gun on all of them and dont worry about a thing.
 

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The front subframe is held by 4 identical bolts!!!!!!!!!!!!!!!

Your manual or whatever it is is wrong !
 

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BS .

Identical bolt , identical torque. Impact gun off and impact gun to put back. No one uses torque wrench on those kind of things. Call any shop and ask , they'll laugh at you.
 

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Discussion Starter · #9 · (Edited)
Also, I don't really care what "shops" do. Most shops probably reuse torque-to-yield bolts and dont hand torque lug bolts. I work on my car because I want it to be done properly. If I want a half-ass job, I'll go to Jiffy Lube.
 

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Also, I don't really care what "shops" do. Most shops probably reuse torque-to-yield bolts and dont hand torque lug bolts. I work on my car because I want it to be done properly. If I want a half-ass job, I'll go to Jiffy Lube.
And you're arguing with an idiot who violates all the engineering wisdom voiced here on this board and in the Bentley manual because...............................??


Think Steve Dinan torques bolts?
Think Turner Motorsports torques bolts?
Think someone has had too much to drink on a Sunday night?
 

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Every bolt sure does have a specific torque but most of them are just guidelines and not a critical point. The reason why every bolt has a specific is so the factory workers can actually assemble the car, once assembled most of the specs will never be used. You know how much force it takes to UNDO the subframe bolt, therefore you apply the same when tightening or greater. Some people are so paranoid that they cant get the correct torque when they dont realize that the job they do doesnt requite precise detail. This is the difference between an weekend DIYer and people who've done these things many times.

I can guarantee you that the only place that TMS uses a torque wrench on are Engine work and when they put wheels on their race cars. No where esle do they use a torque wrench because they have experience and know where its needed and where its not, call them and ask about this front subframe fiasco , I bet they will laugh at you. Dont take my words for it, we have many people on this board who own and operate BMW shops and they will be more then welcome to explain to you that you guys are completely paranoid about something thats not any critical to be paranoid about at all.

There are places where a torque wrench is needed and there are places where its absolutely unnecessary, granted there are torque specs for such little things as bolts for your windshield washer or your airbox
 

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Gotta admit that for most all the things I do on my car, I usually go by feel more than reaching for the torque wrench. Also did lots on many cars over the years and didn't even own a torque wrench. Never had a repair come back to bite me.
That said, I'd of course always use a TR and tightening pattern on a head installation, and think that such things as a reinforcing plate with one-time use bolts deserves a TR. And I abhor the use of an impact wrench on wheel lugs. Too easy to strip and too many people I respect urge the use of a TR here.



If Steve tells me to torque my lug nuts, I'm gonna do it!
See the wheels start at around 5:20 here:
http://www.youtube.com/watch?v=_-b7n_a7VO4
 

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OP...first, did you lose your bolts or you read they were one time use. And is it for the subframe or the braces from one rail to the other?

If you read Bentley again, I think you'll find that they're quoting for a variety of different cars...for one. Did you look at your bolts for a number stamped on the top?

Second if it's one-time use bolt, then just go to the dealer, give them your vin, and tell them what you want.
 

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The front subframe and the front structural brace are two different parts incase people are mixing them up. Front subframe is where the motor mounts and rack bolt to. I believe like other high grade bolts they will have the markings on the top which grade they are.
As for using a torque wrench, I use it on whenever possible. Bolts put on too tight can strip and/or also degrade their quality. there is a reason a spec grade bolt is used and also a torque spec given.
 
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