Xoutpost.com - Stiffening plate bolts

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Quote:

Originally Posted by Omerta (Post 1031565)

Some basic fluid changes and you are now qualified to assure everyone that these engineered bolts are overkill?

A) Its a steel plate on the E53.
B) These bolts fasten the sway bar to the chassis, they also provide lateral support for the undercarriage.
C) Material properties are a real thing. The clamping force will change every time you re-torque those bolts.

Thus it is critical to chassis stiffness in the front. That said, they wiere designed with factors of safety for performance on the track where under normal conditions its unlikely to cause failures for a garage queen.

Don't share bad advice and call it common sense. If you choose not to replace the bolts, that your prerogative. It is not sound practice to reuse TTY bolts. Period.

Dunno about your e53 mate, but the stiffening plate under mind is good old aluminium...

Guys

The X5 had two different plates under neath our vehicles. The aluminum one used until sometime in 2003 and a steel one used after that point until production ended on the E53. All the 4.8is have a steel one. As far as I can tell all the 4.6is had a aluminum one. The 3.0 models had both but when they changed to steel, I have no personal knowledge.

Bolts: The factory used one time fasteners (nuts and bolts), that are torque to yield. Torque to XXX and then 90 degrees more. These nuts will then change their shape and "lock down" with greater force. Yes, they are expensive. 1 year ago they were $25 for a set. Now Higher. Can you use grade 8 bolts with lock washers and get a solid connection for the bars and structural rigidity? With only a few years of auto engineering education/experience, I would say "yep". But I would also post the "no testing done to confirm acceptability" clause.

Bottom Line: Do not use the old nuts. At least replace them with known good grade 8 and lock washers. Just for safety.

Most of us on the forum, are high maintenance DIY who go above and beyond what the normal owners do to 10 year old cars. A lot of us are not the first owners and have spent $$ to get them "just right" once again. The reason? We want everything to work correctly and not leave us stranded somewhere. I like to believe we are care takers of the things we own, not just "users". Hell, I even weekly wash and detail, Qtrly clay and wax my Minivan! :thumbup:

Quote:

Originally Posted by trader4 (Post 1031582)

Same here. So I guess some of us learned more from being under
the car changing oil than others. Also, unless the other poster's
X5 is built very differently than mine, those bolts don't hold the
sway bar to the chassis either.

http://www.etk.cc/bmw/images_etk/B0031982.png

Guys

Look at these two images. Different perspective same bolts on the sway bars also hold the plate to the subframe. According to this parts listing the bolts are the same for 6 and V8

31101096987

I re-use these nuts and bolts, zero issues.

Dealer mechanics re-use them too.

On another note, when doing suspension (control arms etc.), the book says replace the bolts etc. but dealer mechanics re-use the bolts. Zero issues.

Many people here are arm-chair generals lol...So stop worrying about these bolts and nuts. They are big, as someone said above and extremely unlikely to break...

Quote:

Originally Posted by trader4 (Post 1031582)

Also, unless the other poster's
X5 is built very differently than mine, those bolts don't hold the
sway bar to the chassis either.

You said the plate bolts don't bolt the swaybar to the chassis. They do.

(picture stolen from else on Xoutpost)

http://i283.photobucket.com/albums/k...8bmw/fbar1.jpg