Did I Just Trash One of My Struts?...

[detroit]

I've got this pair of SC Bilstein struts that I'm rebuilding. They had some clumps of grease stuck down in the tubes that I wanted to clean up and remove before sticking them in my blasting cabinet. I thought a big pipe cleaner would do the trick, so I picked one up. It's a steel brush. I chucked it up in my drill, and zipped down one of the struts...
To my horror, I found when I pulled it out that I had scored the s**t out of the bore. I didn't realize that there's a nylon or similar sleave pressed into the top of the tube.
Have I just destroyed my strut, or can that sleave be replaced?...

[stownsen914]

Bilstein struts have what should be a brass sleeve inside nearthe top, to guide the strut insert as it moves inside the housing. How badly is it scored?

[detroit]

@stownsen914, I don't think it's brass. It appears to be dark grey in color, and yields under my thumb nail. I wouldn't think brass would scar so quickly from literally a couple of in and outs with a wire brush either. Could be wrong about that though.
As for how bad it is, there is noticeable play between the strut and insert. There's play between the two on the unmolested strut also, but not as much.

[mepstein]

You can buy and replace the plastic sleeves.

[detroit]

Oh, man. Thanks, Mark. I couldn't find anything like that on our host's site. Nor Bilstein's. Any idea where I might acquire them?

[detroit]

Never mind thanks, Mark. Through some Google searches I stumbled upon a write up on this site explaining what's required to change those bushings. I don't really feel like machining up a bunch of tools. I'll send them off to be rebuilt assuming I can find someone to do the job...

Thanks for the responses, fellas.

[PeteKz]

If they're plastic and just scratched, I would not go to the trouble to replace them. They just locate the insert inside the strut.

[stownsen914]

Interesting, my bushing were brass. Perhaps a non stock part. I got them from cgarr as I recall.

[Alan L]

I replaced the bushings in my SC and 930 a yr or so ago. They were somehting like bearing material - soft white metal.
PITA to replace. Getting the old ones out was no fun - had to make a bunch of bits.
Unless I am some how misunderstanding what is going on here.
Alan

[Bill Douglas]

I don't think it does much. I suspect it's just to stop the inner clanging against the outer. If it's still sort of intact I'd just reassemble and see if it works OK.

[LJ851]

The koni and boge struts capture the body of the strut insert inside housing but the Bilstein struts in question are different and “upside down”. The bushings on a Bilstein strut are very important and control the play in the strut assembly since the body of the insert is what is moving up and down in the housing.

[detroit]

Thanks for all the replies, fellas.

I tend to think that LJ851 (Ducati?) is correct here. Play between the strut body and insert will allow the assembly to buckle. A very small amount admittedly, but that's putting loads into the shock for which it was not designed. And, if it's buckling back and forth on the road, that subtle steering geometry change can't possibly be good for handling...
Anyway, I spoke with Craig Garrett last night, who used to provide bushing replacement service. He no longer does. However, he's given me the name of the chap to whom he sent his tooling. I'm going to try to get a hold of him today.
Stay tuned...

[stownsen914]

Correct about not wanting play between the shock insert and the bushing. That's why I had mine replaced. I felt a light knock when shaking the wheel, not unlike what a loose wheel bearing feels like.

[detroit]

One quick correction. The bushings are, in fact, metallic. I must've imagined it yielding under my thumb nail. Thanks for pointing that out...
They must be damned soft though. That wire brush really trashed the surface.

[Alan L]

Mine were soft white metal bushes - like mains bearings. Same sort of material. Took a while to find some - from the UK I think. It is in fact a standard bush/bearing - that just happens to be used in Bilsteins.

"I felt a light knock when shaking the wheel, not unlike what a loose wheel bearing feels like."
To me , it is indistinguisable. I got sucked doen the hole to replace wheel bearings. Still got some play. Couldn't figure it out. Then a yr or so after, I had forgotten I had replaced the bearings (should have checked my notes), and replaced them again. Then I saw my maintenance record and saw I had changed them a few thou K previous. Finally twigged to the fact it may be the strut. Bit of a mission working out how to get the old ones out. Once I had sorted that I proceeded on both the SC and 930 - since I was on a roll.
Alan