I'm currently running Bilstein PSS9's on my 2005 STi sedan. They have been on my car for 3 weeks now. I got them used, from a 05 STi track car that auto crossed on them, but the price was free so I took them and installed them.

A few days ago I started noticing, a clunking sound that only occurs when under 15mph, and coasting. It goes away with acceleration or braking. I've done some research and checked the easy things like lugs and suspension bolts. I have even used an impact gun on all my top nuts on the struts. There was a noticeable clunk when pushing down on the fender area near the coils but the sound goes away after I hit it with the impact gun. An immediate test drive proves the problem corrected but by the end of the following day, the sound is back.

Has anyone had a similar problem, that they've corrected, or any advice on what to try next? I'm usually at the Wednesday night meets in Milpitas if anyone would like to hear the sound in person and try to diagnose.

Thanks in advance for taking the time to read and help out!

 

sway bar endlinks?

 

Have not checked that yet.

I also forgot to mention I did new rotors and pads maybe 4 days before the sound started.

I did just rechecked the top nuts for travel and there is none so the top nuts didn't come loose.

 

Need more info... Do you hear it only going over bumps? How about when turning? Do you here it with the clutch pushed in?

 

Bumpy roads and smooth both. Going straight and turning. Clutch in and out, both in gear and out. All the same sound, no increase or decrease in any of said scenarios. It's also not audible outside the car, but easily heard inside.

 

did you set the preload on the coilovers? You can get clunking from the spring settling each time if the preload isnt setup correctly.

 

I measured everything to make sure I was within the preload min max specs, but that's the only real set up.

Would rocking the car be enough to test that?

 

Rocking the car wont do much. Lift the car up so the wheels are drooping and grab the spring in your hand and try to shake it. If they do move around then they need more preload.

 

Ok, thanks! Sorry I'm pretty green at this stuff haha.

 

no prob, it sounds like the common prob most people have. Just check for movement in the spring or if your able to spin the spring by hand in droop. My guess is that it isn't preloaded enough so the spring is moving around on you. Would make perfect sense with the symptoms your seeing.

 

While researching what you've mentioned to me I discovered this is a common problem with the PSS9's. I read that Bilstein made a kit to remove the clunking from previous sets sold and corrected all future sets from the discovery. So this could be a bigger PITA than I'm capable of haha