BoneStockS4

Long story short I installed my Ohlins based Motorsports in Feb/March of 2005. From day one I had rattling in the rear, that I initially mistook for shot CPP rear control arms. A month or two later I went back to stock arms and the rattling was as bad as it ever was.

I gave up for a while and lived with it, but as the miles piled on I started to get some loud knocking very high up in the rear in addition to the rattling. Calling up Stasis, I found that there was a slight revision to the rear Ohlins valving (front is unchanged) and that a free kit was put together that replaces the upper bushing for rattle free operation.

So last week I had the rear shocks pulled and mailed to Stasis on Monday. Jason and crew turned them around quickly and I had the shocks back by 9:30AM Friday! Not only that, but my 20K miles old shocks look almost new! Not only that, but it looks like they put new bushings in the bottom eyelet as well, and included delrin-like washers to put between the spring and perches. Way to go Stasis! Thanks!

But I digress. The shocks went back in last night, and the loud knocking that had developed after initial install was gone! Yes! Finally!!! BUT... the lower volume rattle is still there... In describing this rattle I would say it sounds like something is bouncing around, high up in the rear. It occurs much more frequently and is louder in volume over bumps that affect one side of the car only. Its much more prevalent at low speeds (with the bushing fix the suspension is silent on the highway, YES!)

My current theory is that the 800lb. springs in the rear are not loaded enough by the weight of the car, and in low speed corners or road imperfection situations, the spring becomes completely unloaded, and is free to bang around on the top perch. The last time I corner balanced the car there was only about 700 to 750lbs. of weight on the rear wheels, so the springs are compressed less than an inch. It wouldn't take much wheel travel to completely unload them. In my mind it all kind of adds up.

I just ordered a set of helper springs from Startup Racing. Hopefully they will help keep the springs from banging around so much. After that I am out of ideas!

Oh, and a public thanks to Davenew! I used his excellent photo's to finally install my Ohlins reservoirs up front. I'll try to snap some pics later after I clean up the car up a bit.

Black Sunshine

My bobcats were not seated properly, infact two of the four springs fell out and the pads were rattling like crazy. I installed new pads (Ferodo DS2500s) and that went away.

Pete5587

simple just one of the springs moved off in rear while installin pads. corrected it and rattle is gone.

ZephyrS4

I hear that form both sides too. Went through the whole winter not realizing it. Ignorrance is bliss.

Gator Al (Al)

I installed the kit Stasis sent me with new bushings and a plastic ring-- it definitely minimized the noise, but it sounds like we have the exact same issue. I'm convinced it is what you think it is-- the unloaded springs rattling around on the perch...

At least now I know nothing is "wrong", but the rattling over rough roads at low speeds still is annoying.

Imolavirus@BuehnEngineering

my helper springs on my Penske setup helped reduce the rattles in my rear

Gator Al (Al)

The good thing is there is no noise anymore except at low speeds over crappy roads.

Imolavirus@BuehnEngineering

Well, to be honest i didn't expect a silet suspension when picking that setup

Gator Al (Al)

I'm a relative nooB, I figured buying the top of the line meant no compromises... live and learn.

BoneStockS4

<ul><li><a href="https://forums.audiworld.com/s4/msgs/2342805.phtml">https://forums.audiworld.com/s4/msgs/2342805.phtml</a</li></ul>