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MrPT

Lifer
I’m in the process of changing the front spring perch on one of my KWs. There is a lot of play between the top mount and the top of the piston rod:

[vimeo]311074038[/vimeo]

Link, in case the embedded vid doesn’t work: https://vimeo.com/311074038

I’ve ordered a strut nut socket and will wait until I have it before I try and disassemble the strut.

The piston rod doesn’t move relative to the spring seat and the nut isn’t loose. Am I right in thinking that this is play due to wear in the top mount bearing and not just under-tightening of the nut?

It would make sense as the struts were upgraded at about 45k but the original top mounts were reused, which means that they are nearly 70k old now.

TIA. :)
 
Looks like it doesn’t it. Once wear starts it quickly escalates as it’s allowed to move more and more. But you know that. :thumbsup:
 
That's as you suspect surely the bearing I'd say. £10 or so each I think so worth changing anyway at that mileage. It's the only part really of the top mount that wears at all I think.
31331090612
 
This is a bit sad, but the process has led to the discovery of two favourite tools. :D

F66ECD2D-1E8C-4DEB-9D8A-C75019C27E41.jpeg

A diesel injector socket and a “rowing spanner”, which is a double-ended 10 and 13mm offset spanner with a nice, tactile shape. Very satisfying to use.
 
bradz said:
When you buy v3's new they come with top mounts.
Click to expand...

I’ve gotten to the point where I’ve realised that now, cheers! Disassembled the top of the strut assembly and at first thought that someone had fitted non-M top mounts, but then looked up pics of the V3s and saw that they come with their own hats. I thought the OEM hats were re-used for some reason - perhaps because people have retrofitted the lower part so that they work with adjustable plates?

I’m struggling to find the right replacement part on the KW site, but even if I do I’ll torque up the 22mm nut properly and see if it is actually bearing play before ordering it.

Spaniarduk said:
[ref]MrPT[/ref], ingenious! :thumbsup:
Click to expand...

It really isn’t, it’s just that the official BMW strut socket tool is about £25 and the injector socket is basically the same thing for a fraction of the price. Have seen people just hit these nuts with an impact gun and hope for the best. :?
 
MrPT said:
It really isn’t, it’s just that the official BMW strut socket tool is about £25 and the injector socket is basically the same thing for a fraction of the price
Click to expand...

Any injector socket? Are they all the same size? Wjat size is the nut at the top of the strut?
 
Spaniarduk said:
MrPT said:
It really isn’t, it’s just that the official BMW strut socket tool is about £25 and the injector socket is basically the same thing for a fraction of the price
Click to expand...

Any injector socket? Are they all the same size? Wjat size is the nut at the top of the strut?
Click to expand...

It’s a Laser 3297 22mm diesel injector socket. £9-10 from eBay.

That’s for the KWs - I’m not sure what size the OEM nut is. RealOEM says M16 so maybe 24mm.
 
BMWZ4MC said:
How did the problem manifest itself MrPT?
Click to expand...

I have a bit of a front end rattle when going over speed bumps etc and I've been going through the process of checking everything. No noticeable play in any strut brace, suspension or ARB nuts/bolts/links/bushes, but it's all due a refresh anyway. I also found one, partially backed-out engine mount bolt but I don't think that this is contributing to the noise.

Unrelated to the above, I'm replacing the lower spring perch as a few of the plastic tabs had broken off (£30 for a new one!) and I noticed the top hat wobble during disassembly. The 22mm nut seemed tight when I first checked it, but since then I've obtained the proper tools for removing and torquing the nut properly so will re-assemble and check for play again. I suspect someone gave it a few blasts with an impact wrench during installation and it's never been properly tight.

I wonder whether these bearings are "lifetime", from KWs perspective, because it doesn't look as if you can buy replacements on their site. Either that or they only replace them during a refurb. They are properly crimped using proprietary means, so I don't know why I ever thought their replacement would be a DIY job!
 
MrPT said:
bradz said:
When you buy v3's new they come with top mounts.
Click to expand...

I’ve gotten to the point where I’ve realised that now, cheers! Disassembled the top of the strut assembly and at first thought that someone had fitted non-M top mounts, but then looked up pics of the V3s and saw that they come with their own hats. I thought the OEM hats were re-used for some reason - perhaps because people have retrofitted the lower part so that they work with adjustable plates?

I’m struggling to find the right replacement part on the KW site, but even if I do I’ll torque up the 22mm nut properly and see if it is actually bearing play before ordering it.
Click to expand...

The KW V3 is delivered with some type of "one size fits all BMW" top coil spring perch.
They are 10 mm wider than the original Z4M top mounts, which is important to keep in mind if you intend to order adjustable top mounts.
 
MrPT said:
BMWZ4MC said:
How did the problem manifest itself MrPT?
Click to expand...

I have a bit of a front end rattle when going over speed bumps etc and I've been going through the process of checking everything. No noticeable play in any strut brace, suspension or ARB nuts/bolts/links/bushes, but it's all due a refresh anyway. I also found one, partially backed-out engine mount bolt but I don't think that this is contributing to the noise.

Unrelated to the above, I'm replacing the lower spring perch as a few of the plastic tabs had broken off (£30 for a new one!) and I noticed the top hat wobble during disassembly. The 22mm nut seemed tight when I first checked it, but since then I've obtained the proper tools for removing and torquing the nut properly so will re-assemble and check for play again. I suspect someone gave it a few blasts with an impact wrench during installation and it's never been properly tight.

I wonder whether these bearings are "lifetime", from KWs perspective, because it doesn't look as if you can buy replacements on their site. Either that or they only replace them during a refurb. They are properly crimped using proprietary means, so I don't know why I ever thought their replacement would be a DIY job!
Click to expand...

Ah ok, thanks. I asked because I’ve suddenly developed a quite marked clunk from the NS front that I can feel transmitted through the steering wheel. The frequency is related to the rate of rotation of the road wheels rather than being associated with vertical movements of the suspension, so I suspect my NS front wheel bearing is rapidly failing. There seems to be slight play and it’s the only remaining original wheel bearing of the four (probably a consequence of lots of track use with semi slick tyres). I haven’t found anything untoward with the track rod or suspension, but given your experience, I should probably have another look.
 
Yeddheng said:
The KW V3 is delivered with some type of "one size fits all BMW" top coil spring perch.
They are 10 mm wider than the original Z4M top mounts, which is important to keep in mind if you intend to order adjustable top mounts.
Click to expand...

This.

Spoke to KW support. Turns out the top mounts are supplied to them by Meyle and were originally produced for the E39 5 series. Looking at the part number (31331091709) I think you are right in that different SKUs for the same part appear to be used on a variety of other models.

So the bearings aren’t replaceable but the whole top mount is for about £25. Progress, thanks all... :)
 
My Zed developed the clunk I described immediately before we went away for Christmas and the New Year, and I didn’t have much time to analyse it before we left. When I got back to Aus last week and drove the car again, it was fairly obvious that the noise was related to suspension travel as much as it was to wheel rotation. I don’t have many tools in Sydney at the moment (they’re somewhere in the Red Sea on a container ship) so I took it to a well-recommended BMW Indy. Happily, he happens to run KW Clubsports on his E46 M3 race car, so he has a fair bit of experience with them. When he removed the damper, he found the source of the clunk to be exactly the same as with yours MrPT. In his opinion, it probably wasn’t assembled correctly and once he’d torqued it up to spec, the problem had gone :)
 
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