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  #16461  
Old 01-30-2024, 11:17 AM
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Quote:
Originally Posted by Henn28 View Post
The straight handle band clamp tool I have will in no way work on the left side inner clap however. Luckily some mechanic that I used in the previous 23 years put a worm gear type clamp on it, which I reused. I wonder if someone makes a 90 degree ear type clamp tool for this job, or are we supposed to drop the stiffener to reach in and clamp the thing! At $28 bucks each those bolts will add quite a bit to the job.

You can also join the "Didn't Replace the Stiffener Bolts" club... I'm going on 40k miles and have put them back in a half dozen times. Still waiting for my car to fold up and crush me inside of it.
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  #16462  
Old 01-30-2024, 11:35 AM
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cheers for the tip! Will have a good look at the spring and shorten if nessecary.

I know the design is poopie, but it's great to have somethong to blame the wife for, for a change
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  #16463  
Old 01-30-2024, 11:36 AM
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Against BMWs strict guidance I've driven both e53 and e70 without the stiffening plate. On the e53 it makes a much bigger difference. The drop in torsional stiffness immediately reminded me of driving my '95 Z28 with the top down. Jiggles from every pothole. On the e70 did not really notice the difference it's clearly a lot more subtle. That said, the biggest problem of either not having the plate or not torqued bolts is the main strength of the plate is to keep the car from becoming a parallelogram from a minor corner impact. Basically bumping into a light pole in a parking lot might total the car without the plate in place with stupid high torque on the bolts. There is reason to the nuttyness.

That said m10.9 spec is 67 Nm and that will get you 7500# force. At yield 9000# the problem is when you "snug" them as if the plate is not structural the clamping force drops so far it stops being structural and you may as well leave the plate off. (The majority of the resuse crowd will fall into this group)

67 becomes 50 Nm when oily (which is pretty common on older X5), so it's impossible to get to a proper clamp Force on a reused bolt, it's just something people will decide to do. The diagonal loading forces become astronomical with a minor corner bump it's definitely best to have maximum tension on the bolts. (But as mentioned I've driven with zero tension on the non existent plate). Just be informed.
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  #16464  
Old 01-30-2024, 11:39 AM
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Originally Posted by guntherrex View Post
cheers for the tip! Will have a good look at the spring and shorten if nessecary.

I know the design is poopie, but it's great to have somethong to blame the wife for, for a change

It doesn't help that on e53 the lock blocks pull effort and puts all the stress on the weakest link. The e70 uses the far smarter "dry fire" disconnect the lever method so there is almost zero force on any part when the door is locked. (which is an incredible oversight since the interior handles on e53 do work the correct way).
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  #16465  
Old 01-30-2024, 12:03 PM
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Originally Posted by andrewwynn View Post

That said m10.9 spec is 67 Nm and that will get you 7500# force. At yield 9000# the problem is when you "snug" them as if the plate is not structural the clamping force drops so far it stops being structural and you may as well leave the plate off. (The majority of the re-use crowd will fall into this group)
I had trouble following this...I have to re-read it a few times.

So , what do you do? It doesn't sound like you re-use...

Do you get non-Genuine 10.9 bolts and use those ? at 67NM?
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  #16466  
Old 01-30-2024, 12:37 PM
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What did you do to / for your E53 today??

I bought aftermarket 12.9 bolts to replace the six I tested to destruction to answer some much needed questions about feasible reuse. I use with Nord lock washers and clean before reassembly to use dry torque values. I can reuse indefinitely as they are only stretched in their elastic zone and steel can act like a spring pretty much forever in that zone.

The most logical reuse thought I came across and I forget who suggested it is to joint at 56 Nm but only angle to 45

That is by far the best compromise!

In my destructive testing even at 90, the plastic deformation didn't start until after the 3rd reuse and even when they started to fail, they turned over 45 before I could feel them stretch. If I have any left I think I'll revisit that thought and see if I can get some solid data but I think the reuse number would jump from 3 to 30-40 when using 45 angle and you'll still get maybe 8000# Clamping force.

The problem with reuse of bolts is the relationship between clamping force and torque goes out the window after the initial use! It's surely why BMW engineered using TTY for these bolts to get a specific reliable force.

When researching this issue when building a 5th wheel hitch I found that when testing 1/2" bolts that should get your about 10000# at 90 ftlb, it took 100 ftlb on the second application and closer to 110 by the 3-4th application.

25% gain in required torque to achieve the same tension. In normal cases where the bolt is pulled in tension it doesn't matter if the preload goes from 10,000 to 8,000 but when the bolt is holding two slippery metal sheets from sliding sideways it needs extreme clamping force to do its job properly.

There are very very cool bolts that actually have a tension indicator you just turn until the red dot lights up in the middle of the bolt. Those would be the best bet not sure if they are available for consumer market.

When we bought our two e53s they both had their stiffening plate removed and replaced before we bought as evidenced by the low torque required to remove the bolts (basically finger tight from an m10 perspective). I am willing to bet that's the majority of e53 on the road so put that into your thoughts on the subject.
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Last edited by andrewwynn; 01-30-2024 at 12:42 PM.
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  #16467  
Old 01-30-2024, 03:03 PM
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Yeah when I first took mine off, one bolt was completely loose, and two were finger tight.

I cleaned them up with the chaser tap and die and reused them at the 56 newton meters and 90 degrees but have low expectations. I've wasted enough money for one time use bolts, I'm about sick of it.

Good call on the aftermarket hardware. I'm definitely going to do that next time that plate is off. Really I would like to weld the nut captive up on top of the subframe / sway bar brackets, so it's easy to remove replace, just gun the bolts in and out. That's the way the f30 is. This thing with the bolt and nut set, well first I didn't know that, and I had a real moment of panic when the first two just kept spinning on me. Oh no .. someone was really working on this car... Everything is stripped I'll never get this thing off. Then when the third one spun I realized what was going on.

I put the wheels on the day before, and then it took me forever to figure out how to get the wrench in there and hold the nut, I ended up having to take the wheels back off. Real pain ... Welding the nuts would make sense.

Myself.. I took it out as a convertible last night for about 30 minutes. The wind buffeting noise at 50 mph is pretty intense. But it runs and drives great. It's going to be pretty solid .. one day. The first gear is pretty awesome.

The black interior pieces are all here I'm still waiting on the second replacement sunroof kit and hopefully will do a perfect job on that second attempt.

I picked up a very clean rear subframe without any rust to send off the powder coat and start "the build". I hope by the end of summer I have a nice clean rear subframe fully built with new or reconditioned parts and just swap it up and on. I visited the local salvage yard and looked at three different e53s. I might take the rear calipers off the one. Not sure if I want anything else off of them. The one did have the panoramic roof and it looked intact. So if I fail again I'm just going to go get that.
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  #16468  
Old 01-30-2024, 03:09 PM
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I have a crescent brand through ratchet that fit absolutely perfect to hold the nut topside but I did flip the bolts nut side down before replacing.

I forgot to mention I replaced the nuts with t-nut that hold themselves so it's still tedious to align initially but with impact it holds itself until tight right to torque wrench it on. (Flipping back to bolt up).

The factory nuts are squished into an oval so they bind so it sounds like you might have cut the threads in an effort to eliminate that feature.

Since that time I replaced my stiffening plate with the one that came with my e70.
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  #16469  
Old 01-31-2024, 10:41 AM
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I'm pretty sure I glazed my brakes and more....

Doing 120 and a car in front of me slammed a stalled Nissan. I went from 120 to 30 while the tires screamed. All this in about 5 car lengths and while enjoying the rain of plastic parts I caught an inner fender liner across the hood. I am almost positive it will buff out as it doesn't feel like scratches.....

PS. My seat is shaped like a traffic cone!!

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  #16470  
Old 01-31-2024, 02:40 PM
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good thing you were wearing your brown underwear
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