Just as an FYI:

If you truly have progressive, nonlinear springs, the mechanism by which the progressive, nonlinear spring rate is obtained is contact between adjacent coils in the spring (no, it's not from changing the diameter or pitch of the coils... there must be contact between coils for a nonlinear response). See spring rates.

I now have progressive springs on the rear of my Cayman. These springs came with the Bilstein Damptronic coilovers.

But an unfortunate side-effect of these springs is that when I go over a sharp bump I hear a "clack" from the coils re-contacting. The coils un-contact as the rear suspension extents after crossing the bump, and re-contact as the suspension compresses to its normal position. This is exacerbated on my car by the complete absense of sound-deadening interior panels (see photo).

Has anyone else with Damptronics noticed this clacking?

Tried Thrust Sheets ?

Swift Springs USA

 

That doesn't seem relevant to the contact issue, although the girl's cute!

 

Yes, I had a clunking sound from the right rear (only) after installing the Bilstein damptronic system in my car last year. I searched around this forum and found a few similar complaints but, to my knowledge, nothing conclusive about the cause was written.

My mechanic couldn't figure it out. He removed and reinstalled that strut twice, to no avail. We ended up getting the right rear strut replaced under warranty from Bilstein. Problem solved.

 

The issue I had was the center top strut threaded column was too tall and hitting the plastic piece in the rear hatch that covers it. I cut about a 1/4" off the top of the the threaded center at the top of the strut and the problem went away. I do know that Bilstein sent me a diagram of how all of the washers, etc. should be inserted when the strut is mounted. I thought I posted that diagram previously, but if not I will when I return. My problem with the noise only occurred over bumps because that was the only time the center piece was making contact with the plastic above it.

 

The issue I had was the center top strut threaded column was too tall and hitting the plastic piece in the rear hatch that covers it. I cut about a 1/4" off the top of the the threaded center at the top of the strut and the problem went away. I do know that Bilstein sent me a diagram of how all of the washers, etc. should be inserted when the strut is mounted. I thought I posted that diagram previously, but if not I will when I return. My problem with the noise only occurred over bumps because that was the only time the center piece was making contact with the plastic above it.

I don't think Fort's car has any plastic covers in it, so that's probably not his problem.

 

The Bilstein representative suggested I do the same repair that Ken made. We did that but the noise did not go away. The true cause of this problem continues to be a mystery.

 

I do not think so. Many, MANY cars use progressive springs from factory and aftermarket without any noises. I agree that there is contact made, but I doubt that it would create noise. I would look elsewhere.

 

You're right - it was something else.

Moderators: I suggest you delete this useless and misleading thread.