Tack weld Bilstein circlips to keep from breaking?

Hi guys!

I have a question, and I thought this would be the best place to get it answered properly!

I rally-x my 1988 BMW 528e with some guys on here, and I need help fixing my rear suspension on the cheap. During one race this year, the circlip/snap ring holding the lower spring perch in place popped off, which dropped the car to the ground:

We threw in a new circlip and finished off the season without another failure, but by the look of it, another failure is only a matter of time:

Yeah, I'm pretty sure it's not supposed to look like that. BTW, these are Bilsteins.

I co-own this car with a buddy, and he is tired of dropping money on it, and to an extent, so am I. Suspension options are somewhat limited on the E28, and I really want a solid lower perch for the spring. OEM struts do have one, but I don't think they're going to be as stiff as I would like, and they're $200. With some help, I could cobble together a cheap coilover setup, but that's going to be a lot of work.

I've heard that it's possible to tack weld the circlip to the shock body, but I'm unsure of how safe it would be to weld it with potentially flammable fluid inside, as well as the integrity of the shock body when it's all said and done. Can anyone shed some light on this topic?

Thank you!

I'd buy a bag of circlips and throw them in the glove compartment.

How about something like this clamped just below the clip. The clip would still hold the perch, the collar would support it and keep it square.

Edit: It's called a split shaft collar and they are available in a multitude of sizes. The one pictured is 2 7/8 inches

In reply to Woody:

That's already done, but if it fails again in the middle of the race, then it could very easily keep me from winning the season, as competition is very tight, and I can't fix it in 10 minutes.

In reply to Toyman01:

That's an interesting device. How well do you think the body of the shock would tolerate getting clamped like that? Also, if the circlip fails, I'm not sure if that thing is really going to stand up to the forces of the spring getting abused on a rally course.

95maxrider wrote: In reply to Toyman01: That's an interesting device. How well do you think the body of the shock would tolerate getting clamped like that? Also, if the circlip fails, I'm not sure if that thing is really going to stand up to the forces of the spring getting abused on a rally course.

Sized properly, the clamping forces would be a perfect circle and the shock body shouldn't have a problem with them. If you slide it up just below the clip, it will stabilize the clip and keep it in the groove. As long as the entire clip stays in the groove, you have no failure and the collar sees almost no load.

Toyman01 wrote:

95maxrider wrote: In reply to Toyman01: That's an interesting device. How well do you think the body of the shock would tolerate getting clamped like that? Also, if the circlip fails, I'm not sure if that thing is really going to stand up to the forces of the spring getting abused on a rally course.

Sized properly, the clamping forces would be a perfect circle and the shock body shouldn't have a problem with them. If you slide it up just below the clip, it will stabilize the clip and keep it in the groove. As long as the entire clip stays in the groove, you have no failure and the collar sees almost no load.

If you wanted to get crazy, you could measure the diameter and thickness of the circlip, put that clamp in a lathe and cut a perfectly sized recess for the clip. Then you could run it right up to the base of the spring plate.

Try safety wiring the ends of the clip together. Also make sure the perch' clip contact point is cut somewhere between square and convex, as to not put force on the edges of the clip.

Have you contacted Bilstein about this?

Another thought, how much compression are you getting on the bump stops before you hit coil bind?

Is that an oem perch in the picture?

There are sleeves that will slide over the circlip in a way that they cannot come out. Sounds like it's time for coilovers.

I think you've got coil bind. They'll tear the perches off the shocks. There's nothing wrong with the circlip setup.

Find someone with a lathe and you will not have this problem anymore. Using that clamp but one that is undersize it can be counter bored so that a lip remains that will fit into the snap ring groove. Once the clamp is tighten the lip will sit in the groove and the rest of the clamp will grip the shock body. I see no way this can fail. You no longer even need the snap ring.

I have some other way of fixing this but they're to involved to post here.

I am familiar with this type set up as I race a VW and my first set of rear shocks use these grooves as well.

I've never had a problem with the Bilstein circlips through a few years of rallycrossing.

95maxrider wrote: In reply to Woody: That's already done, but if it fails again in the middle of the race, then it could very easily keep me from winning the season, as competition is very tight, and I can't fix it in 10 minutes.

This, and I ain't loaning him my car next season just so he can beat me in it

Woody wrote:

Toyman01 wrote:

95maxrider wrote: In reply to Toyman01: That's an interesting device. How well do you think the body of the shock would tolerate getting clamped like that? Also, if the circlip fails, I'm not sure if that thing is really going to stand up to the forces of the spring getting abused on a rally course.

Sized properly, the clamping forces would be a perfect circle and the shock body shouldn't have a problem with them. If you slide it up just below the clip, it will stabilize the clip and keep it in the groove. As long as the entire clip stays in the groove, you have no failure and the collar sees almost no load.

If you wanted to get crazy, you could measure the diameter and thickness of the circlip, put that clamp in a lathe and cut a perfectly sized recess for the clip. Then you could run it right up to the base of the spring plate.

This is what I would do, but I have a lathe.

jimbbski's idea could work as well, my only concern would be the hardness of the collar. That's a lot of force on a thin lip. If it's not hard enough, it will deform or tear. If it's too hard it will crack. The clips are a known hard material so I would find some way to support it.

Why is the perch sitting at an angle?

Assuming it is a flat perch like mine are when properly installed the perch should be flat on the circlip and the lower portion of the perch will be over top of the circlip making it very hard to pop off unless you get coil bind like Keith said. My Autox Miata's and my rallyx RX-7 use the circlip to mount the perch and I have no had issues with them either Koni or Bilstein.

Half of the issue is how well the spring perch fits over the circlip. The recess in the perch should be flat and square and clean and sharp. If it's deformed it will tend to try to roll the circlip over and out of the groove. I had this precise problem w/ the rear Konis on my '02 Civic ep3 hatch. Koni replaced the rears after it happened twice, and they definitely weren't able to coil bind.

moxnix wrote: Why is the perch sitting at an angle? Assuming it is a flat perch like mine are when properly installed the perch should be flat on the circlip and the lower portion of the perch will be over top of the circlip making it very hard to pop off unless you get coil bind like Keith said. My Autox Miata's and my rallyx RX-7 use the circlip to mount the perch and I have no had issues with them either Koni or Bilstein.

btw Nick, ^^ that's Shawn, if you didn't know

That clamp was what I was trying to describe the other night. Link to one: http://www.amazon.com/gp/aw/d/B0063L6T14/ref=mp_s_a_1_16?qid=1419308451&sr=1-16&pi=AC_SY200_QL40

Adding some extra bump stop material might help if it IS coil bind.

Like was mentioned, part of the problem now is that once it's happened once, the groove is likely damaged some making it easier to happen again.

The safety wire cinching the clip ends is interesting if the clip is thick enough. Shouldn't hurt.

I didn't realize that the spring perch was cocked but that isn't right. If the perch is slipping over the clip or even forcing it to deform the clip could come out of it's grove as the poster has said. A new perch that fits snug over the shock body and has a slight counter bore to retain the clip in it's grove should work.