Took a hack saw to it...strut bushings

[onebluemcm]

So, yeah, I got midevil on it. I'll explain. I picked up a lighty used, installed once set of Ground Control struts/Koni yellows from the boards here. The struts are fitted with a lower spring perch for OE or OE-like springs - I have a set of Dinan springs in hand.

As I'm fitting the stock parts to the GC struts I'm realizing that there is not enough thread on the strut to adequately tighten the top nut. As you can see, the hex on the strut shaft is already rounded a bit, probably from the original owner


There aren't really any parts that can be gotten rid of with the stock bushing - you have to use the lower large washer for something for the bump stop to hit, next is the bushing and you have to use the top washer on the stock bushing to provide the upper support for it - at least this is what I thought. So I got to thinking that I'd try to shorten the bushing with it's steel sleeve that slides over the threaded part of the strut rod. I fully realize I'm totally in uncharted water here and it's a hack job at first glance but I don't see how it could really result in premature failure. That said, I'm here to show what I did and get feed back from knowledgable people who really understand this stuff. If I have to get camber plates or something else, so be it I guess.

The stock bushing on the bottom has this ridge of rubber that doesn't really seem to do much. First, I trimmed a little donut of rubber off






Then all I had to do was shorten the steel sleeve - all I needed for the top nut was a few millimeters - I think I shortened it by about 4 - 4.5 mm total. Basically, I could have gone at it with an angle grinder or dremmel but I figured a new, sharp hack saw blade would cut the straightest and create the least heat so as to not damage the rubber. Just had to cut the little protruding part of the sleeve off






After the cut I smoothed it down and flattened it to be sure the lower surface was within 0.001" flat to the top surface of the sleeve. Luckilly, I got really close on the initial cuts and had to do just some minor smoothing to get it basically perfectly flat and parallel to the top surface of the sleeve.

The result was


Much better for the top nut.

The question is, and I am not taking this trivially, have I substantially weakened the bushing? I don't really see how, but I'm looking for educated comments on the matter. I'm a bit nervous about it, but at the same time sort of confident that it will be fine.

I wasn't planning on camber plates now. If I go that route, I don't want anything with a solid upper bearing/bushing - lets not kid, it's a street car that if I'm lucky I'll get on a track for an HPDE or the like. GC has a street camber plate with rubber or urethane upper bushing, any good?

Thanks for any insight as to what I've done.

[ZStig]

i'm no expert, but that looks fine to me.

[3002 tii]

can't comment on the structural integrity but gc plates get good feedback for the most part, only criticism being the way one has to change camber and caster is reverse on those plates relative to other ones. it makes dialing in the suspension slightly more difficult then say, the tck or vorshlags. but like you said, if you're not going to see that much track time, you probably need not worry since you won't be touching the plates after initial alignment.

[The HACK]

I don't know. I would have just gotten a Vorschlag camber plate and be done with it. Unless you plan on competing in stock class where camber plates are not allowed.

Something doesn't seem right, I've got the GC track/school coil-overs on my MZ4 Coupe right now and I can't imagine that same strut set-up needing to hack-up the OEM strut mount in order to fit.

[onebluemcm]

I thought it would be totally plug and play too. I was not expecting a shortage of threads. The way it was, the nylon in the top nut wasn't really engaging threads and I knew I couldn't leav it that way - definitely unsafe.

Don't know what to say could have been removed - I took everything off the stock strut and moved it to the GC strut. I didn't think there was anything that could be left out. It I had left out one of the large "washers", I probably would have had enough thread with the stock length of the steel sleeve in the bushing. But..I'm pretty sure you have to have both of them in there.

If this is stable and works, it's $300+ cheaper than just getting Vorshlags or something else - that is why I figured I'd try it. My unanswered question now is if I go to a camber plate, will I encounter the same issue with a bushing that is too tall?

[The HACK]

Did you try test fitting it without the springs? I know it's a stupid question, but it's hard for me to wrap my head around it. If you have the issue(s) then the previous owner must have the same issue as well.

The ONLY other thing I can think of is the perch underneath for the spring is installed upside down.

[onebluemcm]

Yup. sure did - installed it without the spring and the boot so I could see if something was binding or what not. Nothing of the like. I'm sure the prior owner had the same issue because only the top 1/3 to 1/2 of the hex part is rounded slightly.... In fact, it has zero to do with the spring. I should have taken a pic of the top end of the strut rod. Basically, the shaft is 22mm diameter, smooth - the obvious. There is a shoulder to it with a length of about 15 mm that is a slightly smaller diameter. Above this is the threaded part and finally the hex end with the adjuster. In the diagram, parts 6, then 1, then 3 and finally 4 slide onto the threaded part of the shaft. I don't think you can leave any of them off - there just wasn't enough room from the shoulder up to the hex to fit every thing stacked on. I should have taken pics of all the parts in a real, exploded view.....