I just recently got the HKS RS coilover installed and noticed a "clunk" when going over small bumps or potholes on the driver side rear. I had my shop check for for loose bolts and didn't find a culprit. So now were stuck with no clue why its making the "clunk" sound on the rear driver's side. It sounds like having loose cargo in the rear trunk, not loud, but noticable. I was told that this coilover was quiet compared to other suspension with pillowball mounts, so I was hoping I can find a fix to this.

BTW, I tried installing the GT SPEC lateral bars and my Greddy oil pan wouldn't allow it to fit. In addition, my shop told me the rear lateral bar would not work with my SPC camber arms because of the toe bolts? Since, the front lateral bar didn't fit, I just decided to return the bars and ordered a set of Cusco sways.

Other than the noise coming from the rear, I'm really happy with the ride. I finally got rid of the notorious bounce. With the Cusco front A Arms and SPC rear camber arms, I'm hoping to get back into spec with a 1" Front and 1-1.5" Rear drop. I'm going to raise the rear a tad because my +22 offset with the 285/35's are causing the tires to rub over bumps and potholes. But now comes another problem...I can't find a alignment shop that will clear my front bumper. Now, I'm looking for a good alignment shop in the NY/NJ area that has a alignment rack built underground. Recommendations?

Pic's and a review to come shortly after I get the alignment

 

Check your lower shock mount bolts and also the sways bar linkage. On my Tein Flex's I've had to tighten the lower rear shock bolts twice due to paint wearing off on the bottom u-mount of the rear dampner (the lower mount of the dampner that connects the rear dampner to the control arm). The noise was a clunking noise like you mentioned. The paint slowly wears off on the inside of the u-mount where the bushing comes intact with the paint, creating a slight amount of play for the bolts threads to make noise. Even if the bolt feels tight, crank it down as much as you can. I got about a 1/4 turn out of them and the noise was gone. Btw, I'm kinda faded right now, so sorry if I wasn't that clear in my writing lol. Good luck.

 

I would check the rear springs and spring mounts. The only thing on your rear shocks that would likely clunk is if the shaft nut was loose, which I assume you checked already.

 

Thanks guys, I'm going to bring the Z to my shop and have them check one more time.

 

for alignment, remove your front bumper when you go to get the alignment done, then drive back home and put the bumper back now, that's how I've been doing it with my cars for years--all too low

 

I actually thought about doing this, but I wasn't sure wether or not my sideskirts would clear going up. Was you sideskirts scraping going up the alignment rack? This might actually be the best thing for me to do.

 

its the upper spring mount... thats how it sounds...

 

Hmm, so I'm guessing that you are saying that with aftermarket spring, this is how it sounds and theres no fix to this?

But, what's funny is that the "clunk" sound is only coming from the rear driver's side.

 

It is not because of the springs. It is the install. Mine make non oises at all. I believe Jason was suggesting the same.

 

its not aftermarket springs...

you are removing soft rubber mounts and replacing with pillow ball... Did they put the paper gasket between the upper mount and the body of the car?

the upper spring pirch used from HKS has a thin piece of rubber between the upper mount that bolts up to where the thick rubber spring seat was on top...

The spring is also able to move slightly over the upper spring mount...

Any place where there is a little bit of movement, it makes noise...