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Ok just making sure.

As for the boot, I'd just lift the car so the shock is extended then pull the boot out from under the spring seat. Lowering springs barely have any tension (preload) when the shock is fully extended. Just to be clear the strut shaft and boot does not turn when the steering wheel is turned. It's the strut body and spring that turns together with the wheel.
 

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Discussion Starter #84
Ok just making sure.

As for the boot, I'd just lift the car so the shock is extended then pull the boot out from under the spring seat. Lowering springs barely have any tension (preload) when the shock is fully extended. Just to be clear the strut shaft and boot does not turn when the steering wheel is turned. It's the strut body and spring that turns together with the wheel.
I appreciate the extra pair of eyes!

I am reading that the B6's are actually made for OE springs, not lowering springs. However, I'm seeing this isn't a problem other than the strut is basically always preloaded to some degree when the whole assembly is put together and torqued to spec. This may eventually cause premature wear, failure, etc. I'm taking bets on which blows first, the strut or the engine. Not gonna worry about it.

Thanks for your clarifying statement re: shaft/boot turning. I guess the net result is the same, the chromed insert twists inside of the strut body to facilitate a twist, a turn. But i understand what you're saying, it's the guide support and upper spring pocket w/axial cage bearing (parts 1, 6[0]) that allow for the turn.

Bilstein says:

The boot is not glued to the chrome insert it is just a tight press fit. It may loosen up over time.
I see what they mean now. On the disassembled strut, the boot does in fact spin freely on both top and bottom ends - no adhesive is used. The lower spring pad has a lip that effectively holds the bottom of the boot in place - I don't think that end should be moving.

However, what I think is happening here is that at the very top of the boot, there is just a little bit of excess plastic molding from the boot that gets pinched between part 7[0] and the start of the slip/threaded section of the chromed strut insert/rod, which doesn't allow the chromed strut insert/rod to twist without also twisting the boot around:

939290




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[0] RealOEM.com - Online BMW Parts Catalog
 

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On the B16's it's the bottom of the boot that moves. I wouldn't touch the top of the boot, but that's just my opinion.
 

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Discussion Starter #87
What's pinching at the top of the boot is clearly excess molding from the plastic boot, i'm certain now that's what's getting pinched and causing the boot to become deformed. It's a few millimetre or two, I'll just give it a shave so it's less-than-flush from where the pinch point is.
 

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Discussion Starter #88
Shaving off the tippy top of the excess boot material seemed to do the trck. The boot now rotates freely as I suspected it should have all along.

But no victory comes without a cost. In the process, I stripped the 7mm hex used to secure the strut shaft while the bolt is being torqued. The hex stripped well before my torque wrench hit 110Nm (110Nm is the prescribed torque per Bilstein's documentation, given the threaded end of the shaft is of size M16). I suspect that I ran the nut past the threads. I also suspect that since these are aftermarket K&N lowering springs, the OE springs would have provided more rotational friction or force against the guide support, which was probably figured in to the 110Nm suggestion per the documentation.

I've had an email thread going with Bilstein and they've been nothing but awesome, providing support, diagrams, and technical assistance. They've got a customer for life, that's for sure. My last response was explaining all of this, and then asking if this was a case of installer error and I'm now SOL, or if this is covered under some magic Bilstein replacement warranty. I won't be surprised or disappointed either way, just looking for a little direction. I had also asked them if that 110Nm torque spec was still appropriate for aftermarket lowering springs given at the same compressed distance as OEM springs, they wouldn't provide nearly the same amount of force as OEM springs would.

I'm just rambling at this point. Hope my notes help someone else in the future. Either way, it's still a fun little project. But I'm going to end up having to sell myself on the street corner to pay for it.
 

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so glad i came up on this tread, ive had both my front and rear shocks and struts replaced with these bilstiens and never knew about this L/R set up since i had my indy shop take care of it.. now im curious to see if it was set up correctly, but what really stood out was the set up on how our springs sit on the perch. reason is becasue when i was my car i like to take off the wheels and really get the dirt out and when i jack up the car i notice my springs (H&R) come loose and i really never paid attention on how they are supposed to sit and to my lack of knowledge i have been sitting them wrong.. i will definitely be adjusting them and placing them the right way asap.. thank you OP for this info and all who have contributed :D
 

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Discussion Starter #91
so glad i came up on this tread, ive had both my front and rear shocks and struts replaced with these bilstiens and never knew about this L/R set up since i had my indy shop take care of it.. now im curious to see if it was set up correctly, but what really stood out was the set up on how our springs sit on the perch. reason is becasue when i was my car i like to take off the wheels and really get the dirt out and when i jack up the car i notice my springs (H&R) come loose and i really never paid attention on how they are supposed to sit and to my lack of knowledge i have been sitting them wrong.. i will definitely be adjusting them and placing them the right way asap.. thank you OP for this info and all who have contributed :D
Woohoo! See my last response, glad this information is helping others along the way, even if some of the questions are silly :)
 

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Discussion Starter #94
I'm back! Now, with even more new parts!

Ended up getting my steering rack back. $480 out the door for the rebuild. It looks real nice, Clark. Going to start putting the rest of it back together tonight.

As I mentioned earlier, I stripped one of the strut hex on the top of the strut rod, while I was tightening the nut. Bilstein manual says 110Nm for this M16 equivalent strut rod thread, But, I stripped the hex well before that. The TIS says these nuts should only see 64Nm[0]. That's also what I saw in a post[1]. There's not much else to go on here. Bilstein email support, although immensely helpful and informative, just told me to take the assembly to a qualified shop.

So, which is it? 110Nm or 64Nm? Because that's a huge difference.


[0] (2AZ "Shock absorber piston rod on thrust bearing") https://www.newtis.info/tisv2/a/en/e60-m5-lim/repair-manuals/31-front-axle-front-suspension/31-31-spring-struts/5ZQTc4o
[1] Replacing springs...Need torque spec for dampers
 

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good question. I'd just stick with the TIS, since it is lower, can also re-check torque for a while until you feel comfortable that it is not getting loose.
 

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Discussion Starter #96
That's what I was thinking. Even though the rod ends are of the same size and thread type, the Bilsteins may be made of a different stronger alloy where a higher torque is ok. But, given my experience, I'm not sure that's the case, unless I did something wrong.
 

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I sometimes find that I am over-torquing because something on the wrench is just a wee bit crooked and gives the torque wrench a false sense of where it is at.
 

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Discussion Starter #98
Sure, been there before. Granted I'm using a crow's foot to grip the nut but using a 90 degree offset, the moment arm doesn't change. The match is the same. I'm not using it as an "extension" like one might, increasing the moment arm and applying more torque than desired.
 

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I've noticed torque problems with a hex that wasn't quite tight enough, so the hex bit was turning inside the hex bolt, causing torque reading to be off. maybe that could occur with crows feet too. my crows feet don't always fit so well when I'm doing what you describe. why are you using crows? is a long socket not tall enough?
 

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Discussion Starter #100
I had considered that the hex I was using was perhaps old, rounded corners, etc. It's not unforgiving tight but it's not particularly loose, either. Though when torque is applied, it doesn't really care what anyone thinks, it just does its thing.

I'm using a crows foot to tighten the nut from the side, as I hold the shaft in place with the hex. The only hollow socket I could find for doing this a more traditional way, I got the runaround from a popular online European online parts outlet that shall not be named, and after a few weeks of delays, told them to just cancel the whole order. Not to mention, I needed a crows foot set :)
 
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