That would be an X5 with serious issues. I think 5-10 times a year would be in the category of an exception rather than the norm. I've worked on my X5 since CPO warranty ended (2011 thereabouts) and I've had to drop the reinforcement plate may be 3-4 times in 8 years.

2006 bought new. Haven't had to drop the plate yet. I have a slow leak on the pan gasket. May have to drop the plate to replace that, but nothing else.

Fastenal, Bolt Depot, etc. will sell you very similar Class 10.9 bolts for a fraction of the cost BMW charges. If you feel the need to replace them, at least pay a reasonable price for the bolts.

AM.

Subjective as to when that "particular set of parameter prove it is a fact based process." Not every standard practice is backed up by engineer reports and experimental testing, or is even fact based. IE: BMW used to recommend 15000 mile OCI... nobody who valued their BMW followed that recommendation. Standard practice was 5000-8000 mile intervals among car enthusiasts.

Subjective. It has nothing to do with it for you. It might be the only factor to someone else, or a contributing factor to yet another person.

As to the plate needing to be dropped 5-10 times a year... mine has been off 3 times so far (once for sway bar bushings, once for cleaning/degreasing to track an oil leak, and I don't remember why the third time... maybe for fun?). Will be off again when I do the differential fluid in the coming weeks. Again, we are talking a subjective point of view. 5-10 times sounds like a lot to some of you, but to me, I'm likely to hit at least 5 this year. Dropping that plate is barely past removing wheels/tires to me, which I do a lot for cleaning. Am I strange? Probably. Certainly wouldn't be the first time I'd been called that.

How many times one drops the plate a year is not subjective, it is not a personal opinion. Personal experience is not subjective, it's what we have experienced. I wasn't challenging how many times anyone would need to drop the plate 5 times a year. I was just interested as to why so many times. I thought you were saying most people drop the plate 5 times a year.

Put aside common practice, standard practice or whatever and focus only on the bolts. The bolts are torque to yield bolts. Torque to yield bolts are designed to be used only once, never reused. It doesn't matter where they they are installed.

Very well. We'll change the terminology to common practice.

Put aside common practice, standard practice or whatever and focus only on the bolts. The bolts are torque to yield bolts. Torque to yield bolts are designed to be used only once, never reused. It doesn't matter where they they are installed.[/QUOTE]

:thumbup: on the attempt to clarify terminology. That usually helps. But while we're trying to keep the discussion precise and positive, I'll point out an error in your second sentence here.
"The bolts are torque to yield bolts."

That's not true. They are regular M10 - 1.5 x 55mm, class 10.9, hex head with captive flat washer, and a 10.9 hex nut with flange ... nuts and bolts. Some bolts are specially designed to be used in a torque to yield application, for example with a long unthreaded reduced diameter neck, so all the yield happens there rather than in the threaded section. These are not. They are regular bolts.

BMW specifies that they be torqued using an initial torque plus an angle. TTA. They also specify that they be replaced when removed, which suggests that they are TTY, or torque-to-yield (that following the TTA spec will cause plastic deformation). But it is not 100% certain that they yield when following the TTA specs. To be careful, I assume they do.

So in short, they are regular bolts that may be used in a TTY application.

Carry on. :thumbup:


EDIT - and a similar situation I thought of just now is the breakaway bolts on the auger shafts of my Honda snowblower. They're sold by your Honda snowblower dealer as special bolts, and when I bought the blower I bought a 10-pack for convenience. But as my supply dwindled and I looked into it, they are just M6 hex head, Class 8.8 bolts. Not even annealed or anything. Regular bolts, used in a breakaway application. Which makes sense, of course. Why make something special (like an annealed M10 when you can just use a standard version of a regular bolt). Same idea.

:thumbup: on the attempt to clarify terminology. That usually helps. But while we're trying to keep the discussion precise and positive, I'll point out an error in your second sentence here.
"The bolts are torque to yield bolts."

That's not true. They are regular M10 - 1.5 x 55mm, class 10.9, hex head with captive flat washer, and a 10.9 hex nut with flange ... nuts and bolts. Some bolts are specially designed to be used in a torque to yield application, for example with a long unthreaded reduced diameter neck, so all the yield happens there rather than in the threaded section. These are not. They are regular bolts.
Never heard they are standard bolts before. Where did you find documentation? Great! Anybody have a link to the exact bolt?

BMW specifies that they be torqued using an initial torque plus an angle. TTA. They also specify that they be replaced when removed, which suggests that they are TTY, or torque-to-yield (that following the TTA spec will cause plastic deformation). But it is not 100% certain that they yield when following the TTA specs. To be careful, I assume they do.

Didn't you just write that you assume there is plastic deformation (stretched to point they won't return to original specs)? That means they are not reusable. Standard or otherwise. If there is plastic deformation they should not be used again as the clamping power will be less than spec. We can't be 100% sure but oh well?

So in short, there are regular bolts that may be used in a TTY application.
So BMW states the torquing process of a TTY bolt just for grins, so forums can debate this forever?

Carry on. :thumbup:


EDIT - and a similar situation I thought of just now is the breakaway bolts on the auger shafts of my Honda snowblower. They're sold by your Honda snowblower dealer as special bolts, and when I bought the blower I bought a 10-pack for convenience. But as my supply dwindled and I looked into it, they are just M6 hex head, Class 8.8 bolts. Not even annealed or anything. Regular bolts, used in a breakaway application. Which makes sense, of course. Why make something special (like an annealed M10 when you can just use a standard version of a regular bolt). Same idea.[/QUOTE]

oldskewel is correct,

I have removed the bolt many times and compare it against a brand-new bolt.
There is no deformity of the old bolt from repeated tightening and loosening.
In other words, the old bolt does not lengthen when compared with a brand-new bolt.

The fact that a bolt is angle-tightened does not mean it is a "use-once-and-discard" type of bolt.

This has been a funny thread, especially if read by BMW or indy mechanics, as they do not replace these bolts.

^ Thank you! I was going to order one of these bolts in my next fcp order just measure it. LoL

Thank you to oldskewel as well. I was curious if they were even tty bolts or just used in a tta application. I was going to ask what was making us assume these were tty bolts... The torquing procedure alone? I recently did the complete front suspension on the wife's e70 and a few of those use a tta torque procedure as well. But are not stretch or tty bolts.