New Strut Brace.... Must have mod!!
- Thread starter Hotride
- Start date
Mangozac said:
But as you remove the tower mounting nuts, won't the weight of the car pressure the struts out of their initial camber setting?
Aren't wheel alignments pretty cheap? It is $60 at my local tyre shop so who cares, but I don't remember my strut tops moving when I unbolted them. I am away snowboarding ATM, but I will get a wheel alignment when I return home.
Bonnet sensor is for the alarm, if someone tries to open the bonnet when car is locked an alarm goes off. If you remove the bonnet sensor there is no warning light. Mine was faulty when I bought the car, so I removed it for about 3 months with no issues. I have not been able to refit it yet, asit will require some sort of custom bracket to refit. But I will try a few ideas I have when I get home
Bonnet sensor is for the alarm, if someone tries to open the bonnet when car is locked an alarm goes off. If you remove the bonnet sensor there is no warning light. Mine was faulty when I bought the car, so I removed it for about 3 months with no issues. I have not been able to refit it yet, asit will require some sort of custom bracket to refit. But I will try a few ideas I have when I get home
If that's so, then what's this on about? http://www.bimmerfest.com/forums/showpost.php?p=5960602&postcount=8Mangozac said:
I would say that if the little centering/alignment pin is still in place, and you are careful not to shift weight on the car during the procedure, nothing should move. But OTOH, to maximise the benefit of your new brace, a fresh alignment would be in order.
billygilly
Active member
Just set the torque wrench and I'm pretty scared, is it definately 32nm.. Seems pretty high
You know, 32nm would be appropriate if the fastener is in a high strength class, otherwise 25nm would be more realistic. That said, neither torque is really that huge, I shouldn't think that in itself would cause a failure, there must be other contributing factors such as previous over torqueing, metal fatigue, corrosion, impurities in manufacturing process, etc.
But then consider this fastener isn't really load bearing, it only provides clamping force to the tower/brace to hold the strut top in proper position. There's not really much side load from the strut to the tower, the brace helps more by stiffening the entire front clip assembly, rather than just holding the towers in place. We don't really need a huge clamping force here, but there must be enough to hold the parts rigidly without any play at all. A low clamping force completely negates the purpose of a brace. In this light, 32nm IS reasonable IF the fastener material is of a high enough strength class. So, is it? I have no idea.
You can achieve higher clamping force with lower torque by using lubricant, but that could be detrimental the friction we are trying to develop. If it were me, I would sparingly apply moderate thread lock to provide some lubrication and insurance against loosening, then torque to 25nm.
But then consider this fastener isn't really load bearing, it only provides clamping force to the tower/brace to hold the strut top in proper position. There's not really much side load from the strut to the tower, the brace helps more by stiffening the entire front clip assembly, rather than just holding the towers in place. We don't really need a huge clamping force here, but there must be enough to hold the parts rigidly without any play at all. A low clamping force completely negates the purpose of a brace. In this light, 32nm IS reasonable IF the fastener material is of a high enough strength class. So, is it? I have no idea.
You can achieve higher clamping force with lower torque by using lubricant, but that could be detrimental the friction we are trying to develop. If it were me, I would sparingly apply moderate thread lock to provide some lubrication and insurance against loosening, then torque to 25nm.
I'm with you on that, it just seems wrong! I've never had this apart, but based on the wide shouldered nuts, the holes are simply oversized, but not slotted. It's impossible for this to provide any significant adjustment. I think camber is roughly correct off the assembly line based solely on geometry of the parts. The adjustment provided is only for fine tuning. If your camber is truly off, then something is bent. Either replace or straighten the offending part or resort to aftermarket solutions.Mangozac said:
billygilly
Active member
Cheers guys, fingers crossed
But BMW should know and should have specified the torque setting appropriately.bcworkz said:
I agree! I mashed up the control arm on my last car which in turn shunted the steering rack and a few bits and was only able to get the camber correct because I had previously fitted coilover suspension with camber adjustment plates. That's why I was so certain that there wasn't enough adjustment available in this case!bcworkz said:
BettyBmw03
Member
Hotride,
just wondering what you ever did with the alarm bonnet? I am still on the fence with this. thanks
just wondering what you ever did with the alarm bonnet? I am still on the fence with this. thanks
BettyBmw03
Member
Anyone else solve the alarm fitment with these?
Thought I would necro this thread by adding my experience as it comes up on Google search (and was the first thread I personally read when researching this strut brace).
I've just installed it this morning and I can totally see why 35nm would/could snap the bolt clean off. When removing, it didn't take much force at all (just regular palm pressure with a regular socket wrench) and I've done a lot of kms with zero issues suspension wise. I should add that I also took time to inspect the bolts themselves for any corrosion etc.
For mine, I noticed that the brace didn't quite slot over the bolts as comfortable as I wouldve liked (it kept JUUUST fouling the edges of the bolts and I did not feel like forcing/flexing it over the threads). I ended up filing down some of the powder coating/finish and then it slotted on fine.
Then I fastened it down side by side so it could spread evenly - I noticed that the brace wasn't sitting 100% flat/flush over the tower but as I started fastening, it evened out.
In the end, having looked through this thread and other's experiences with torquing these down (and snapping them), i started at 18nm and worked my way up to ~20-22nm. Is that enough? I'm not sure, but if it loosens, it's an easy enough bit to tighten up and wouldn't be a total disaster if you were trotting around down.
I think one thing that the 35nm spec might not take into account is that with the brace in, the threads you're tightening over aren't the standard - they're further out. Whether this makes a difference I don't know as I'm not an engineer but that's something to consider i guess? An actual explanation below....
Just for the sake of it, marked with a sharpy the nut position.
I know you asked this 5 years ago (lol) but for anyone else, the brace has a cutout for the pin (I'm assuming you were referring to the knobby on the top of the tower).
I've just installed it this morning and I can totally see why 35nm would/could snap the bolt clean off. When removing, it didn't take much force at all (just regular palm pressure with a regular socket wrench) and I've done a lot of kms with zero issues suspension wise. I should add that I also took time to inspect the bolts themselves for any corrosion etc.
For mine, I noticed that the brace didn't quite slot over the bolts as comfortable as I wouldve liked (it kept JUUUST fouling the edges of the bolts and I did not feel like forcing/flexing it over the threads). I ended up filing down some of the powder coating/finish and then it slotted on fine.
Then I fastened it down side by side so it could spread evenly - I noticed that the brace wasn't sitting 100% flat/flush over the tower but as I started fastening, it evened out.
I think one thing that the 35nm spec might not take into account is that with the brace in, the threads you're tightening over aren't the standard - they're further out. Whether this makes a difference I don't know as I'm not an engineer but that's something to consider i guess?
Just for the sake of it, marked with a sharpy the nut position.
I know you asked this 5 years ago (lol) but for anyone else, the brace has a cutout for the pin (I'm assuming you were referring to the knobby on the top of the tower).
A quick point which might explain why torquing to 35nm can lead to snapping off.... the nuts are an engineered one-use self-locking type, BMW recommend new ones are used each time as the internal surface is designed to provide friction lock to stop them undoing. Re-using them means they no longer offer the same resistance and your torque readings are meaningless. Re-use can lead to incorrect torque readings, over-tightening and mushrooming/fracturing of the mounts as well.
The same part number is used on several BMW's and Mini's, they are a one-time use item and quite fragile and a LOT of Mini's in particular have reports of them fracturing when re-used. A set is expensive from BMW but it's an 'engineered' nut that can cause real problems if abused, personally I'd only use genuine ones, anything else (ebay etc) is an unknown quantity.
The same part number is used on several BMW's and Mini's, they are a one-time use item and quite fragile and a LOT of Mini's in particular have reports of them fracturing when re-used. A set is expensive from BMW but it's an 'engineered' nut that can cause real problems if abused, personally I'd only use genuine ones, anything else (ebay etc) is an unknown quantity.
The nuts when torqued on their first use are deformed by a predetermined amount (the torque setting given). When they are removed they do not return to their virgin/un-torqued state. If used again and tighted even to the same torque setting (adding the same degree of deformation) in reality there is a compound deformation (of the two attempts) which deforms them tighter then the design requires and beyond the force required to shear the bolt (don't know about you but I can't recall ever seeing a nut strip the threads its always the bolt that gives).
Engineers say that the 'ideal' torque for any nut and bolt is 'half a turn before the bolt snaps' - and no doubt BMW will be close to this the first time the fixing was used (albeit with a little safety margin). If its single use (very common on drive shaft hub bolts/nuts) that's just what it is - one use.
Single use nuts / bolts are expensive for a reason - try to resist the ebay 'pre owned' bargains
My mate used 'pre owned' drive shaft bolts but that's another story.
Engineers say that the 'ideal' torque for any nut and bolt is 'half a turn before the bolt snaps' - and no doubt BMW will be close to this the first time the fixing was used (albeit with a little safety margin). If its single use (very common on drive shaft hub bolts/nuts) that's just what it is - one use.
Single use nuts / bolts are expensive for a reason - try to resist the ebay 'pre owned' bargains
My mate used 'pre owned' drive shaft bolts but that's another story.
