Stiffening plate removal / reinstallation

[andrewwynn]

Depends how close to tolerance. If for example testing five gives you no result closer than 80% of proof stress I would be satisfied that it's all safety factor fortunately I found some 5 packs of galvanized M10 for a very good price.


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[bcredliner]

Originally Posted by cn90

When I replaced the OFH gasket, I left the plate off for about 3 weeks just to monitor for any oil leak. During that time, I re-installed only the bolts holding the sway bar, the X5 drove the same w/o the plate.

The Fastenal article above does not kill anything. It is just another article on the nuts and bolts.

Do this: remove only one bolt (the bolt in the front area near the front radiator). Then remove one wheel bolt. Now compare them. They are similar in size and strength. And we don't replace the wheel bolts, which are subjected to much harsher condition (shearing force, hitting pot holes etc.).

Comparing a lug bolt and plate bolt doesn't mean anything. Similar and look the same does not mean they are even close to being the same. They can look exactly the same and have entirely different specs.

If the data from experts is not accepted why should anyone accept your DIY anecdotal input as such? If a conclusion is as based on assumptions , not matter how many times it is posted or variations of same are introduced the conclusive is still flawed.

[cn90]

I don't need anyone to accept my DIY.
My conclusion is based on real life experience.

Your Fastenal article above serves little purpose.
We already know all that stuff.

Now, do a google search using key words "bmw stiffening plate bolt reuse", you will see that 99% of the posts are from DIYers at home and not mechanics. Naturally, these DIYers are concerned b/c they read Bentley manual etc.

Just got off the phone with my cousin, who owns a BMW indy shop in Los Angeles area. All he does all day is BMWs and nothing else. And he has repaired BMW for 30 years. He just laughed at this thread b/c he re-uses the bolts all the time and does not recall one incidence of any problem. He said these are not TTY bolts. rather, they are TTA bolts.
BTW, the only time he ever replaces the bolts routinely is the head gasket job and that is about it fixing BMWs all day long...

So, there you go, you can sit here and argue all you want...

[Attacking Mid]

Originally Posted by cn90

...He just laughed at this thread b/c he re-uses the bolts all the time... the only time he ever replaces the bolts routinely is the head gasket job

Does he reuse the aluminum bolts that are prevalent on the N-series engines? I HAVE reused them in a pinch, but replace them if at all possible.

AM.

[crystalworks]

Originally Posted by bcredliner

I am not saying the bolts can't be reused. I think there is lots of indications they can. I am saying nothing presented so far is adequate to prove they can.

Again, that's fine. It is your personal choice to reuse the bolts based one a statement from BMW, Bentley, etc. Have at it. Literally, nothing posted would satisfy your doubt. Again, fine. But don't discount people who have years of experience dealing with these bolts on tens (or possibly hundreds in the case of dealership or indy mechanics) of vehicles. You have made your decision, and I (don't know about everyone else) respect it.

But when people come here asking if they can reuse the bolts, it's because they have already read the statement you are referring to. They are looking for real world experience from those who have NOT replaced their bolts. Your input is something they already know. If you had proof of some negative result of reusing them, that would be valid input. I include in every response (I think) to someone asking if the bolts can be reused that one member reported possible noises from his stiffening plate and/or the bolts.

As to the comment regarding mechanics reading this thread and laughing being a personal insult. If you are offended by that, or took it as a personal slight, you have thin skin. Mechanics reuse these bolts all day long. They'd laugh.

Originally Posted by X5only

Well done Bcredliner, that article should surely kill this thread.

Sarcasm?

And congrats on finding a way to get the bolts cheap. Seriously. For those who the main factor is the cost that should help considerably.

[andrewwynn]

Originally Posted by bcredliner

See paragraph one. https://www.fastenal.com/en/77/reuse-of-fasteners

I read the whole article. Very good read. I was saying the same thing regarding if it's ok to reuse a bolt. All my "it is ok" math is based on don't exceed proof load.

I did my first exam of an old bolt today but since I don't have the "before" nothing conclusive yet, but preliminary measurements suggest the bolts are actually strained past proof, and would have a cycle lifespan like the above article explains. (Eg ok to use 5 times).

I've only measured the bolt after use and I measured a slightly lower than expected thread pitch.


Over the first 9mm the threads seem to line up on a 2/3 thread per mm or 1.5mm/thread as expected.



But at 36mm (24 threads), it's clearly about 36.2 mm or 1/2% elongated.

That does strongly suggest the TTA torque is also TTY.

I'm getting excited to get some measurements made

[cn90]

Could you do the same measurement for a wheel bolt?
We re-use wheel bolts all the time and wonder what the wheel bolts look like after 15 years of service...

[Crowz]

Originally Posted by cn90

Could you do the same measurement for a wheel bolt?
We re-use wheel bolts all the time and wonder what the wheel bolts look like after 15 years of service...

Or even shorter time periods after tire shops nail them with air tools....

[crystalworks]

Originally Posted by andrewwynn

I've only measured the bolt after use and I measured a slightly lower than expected thread pitch.

But at 36mm (24 threads), it's clearly about 36.2 mm or 1/2% elongated.

That does strongly suggest the TTA torque is also TTY.

I'm getting excited to get some measurements made

Interesting. Thanks for the pics. I'll have to measure mine as well next time they are off. Get a second point of reference. But to throw a wrench into measuring the old bolts... we don't know their history of torquing. Most mechanics just hit these with an impact, give it a few good uggaduggas, and call it a day.

[bcredliner]

Originally Posted by cn90

I don't need anyone to accept my DIY.
My conclusion is based on real life experience.
Real life experience is interesting to hear but so far you have presented no facts that endorse real life experience.

Your Fastenal article above serves little purpose.
We already know all that stuff.
If you know all the stuff why are you disagreeing with me?

Now, do a google search using key words "bmw stiffening plate bolt reuse", you will see that 99% of the posts are from DIYers at home and not mechanics. Naturally, these DIYers are concerned b/c they read Bentley manual etc.
The point was not the DIY information didn't count for anything.The point was that DIY conclusions are based on experience that can't be blindly accepted as conclusive proof. If I state my experience are you going to accept that as factual?

Just got off the phone with my cousin, who owns a BMW indy shop in Los Angeles area. All he does all day is BMWs and nothing else. And he has repaired BMW for 30 years. He just laughed at this thread b/c he re-uses the bolts all the time and does not recall one incidence of any problem. He said these are not TTY bolts. rather, they are TTA bolts.
BTW, the only time he ever replaces the bolts routinely is the head gasket job and that is about it fixing BMWs all day long...TTA is process for achieving a particular clamping power. It is not a kind of bolt. Sometimes the TTA process results in plastic deformation and sometimes it does not. It depends on the particular bolt. I have said many times that I don't know if the bolts should be reused or not. I have been saying your conclusion the bolts can be reused has no factual foundation. All you have been doing is making the same claims over and over sometimes in different words.

So, there you go, you can sit here and argue all you want...

I'm not arguing. I don't know what the correct answer is. I'm just asking you to provide expert proof to support what you have heard and your experience.