I think I have finally found the cause of irritating rear rattle (see video below) from my 07 350z so I just thought I would post my conclusion.

I know many have tried making their own spacer to fill in the small gap between the shock fork and bolt and it has worked for a lot of people, and for all I know that may be the culprit for many of you. But I tried this simple fix and it literally changed nothing in regards to the loud rattle. Right now my car has about 40,000 miles so perhaps this fix will apply to those who have less miles on their z, because this rattle was apparent when I bought the car with 30,000 miles on it.

Being that the simple PEX tubing fix did not work for me I went on to replace the shocks (d-specs). At first, the noise was gone but it came back only two days later. This led me to believe that it had to be the rear shock mounts. I then removed the shocks again and examined the shock mounts carefully and I found that the rubber bushings were worn and stretched which could allow movement at the top of the shock shaft, which could explain why the sound is so odd.

I then figured I would get replacement bushings but I would most likely end up with the same rattle over time. So I ended up trying the kyb shock mount kit (only $35 for both mounts), and when I examined the mounts it was obvious that these mounts were much better, the main reason being that the top of them is composed of metal which will prevent the top part of the shock shaft from moving around and stretching the rubber bushing.

As of today the sound is completely gone, and my car is finally enjoyable again. I hope this fix truly works and I will post a week from now on whether or not the sound is gone for good.


video link (this is not my video, but it is this exact sound)
http://www.flickr.com/photos/27906623@N07/5433878625/

 

wow thanks for posting. i have the same noise. what a terrible noise for such a nice car to have. link to the exact part u got? i need to do this

 

Great idea. I'd also like more specific info about the source for these KYB parts. TIA.

 

The part number is SM5482, you can also google "350z rear shock mount" and their should be a number sellers selling the kyb shock mount kit. The kit is for one mount only so if you plan on doing two, be sure to get 2 kits.

 

Thanks very much - looking forward to doing this.

 

So it's been a week and the sound is still gone, whether it is cold or hot. I'm glad it's fixed but now that the rear is so quite, I hear all the other loud irritating rattles that the car has. One rattle at a time I guess.

 

thanks for the fix, I was hearing this tonight and wondering what it was. It sounded like a mount but I knew for sure it wouldnt be that with such low mileage. Ill order these asap!

 

I've had this rattle on one of my rear coils, turns out the fork mount just wasn't tight enough. I gave it some extra torque and the rattle was gone for good.

 

So its been some time now, and I can officially say that this was the cause of my issue. Haven't heard even the slightest of sounds coming from the rear since. Hope it helps or has helped those who have the same problem.