Diagnose this noise for me

Wheels, Suspension, Brakes & Tyres questions and answers

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Trackphotos
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Diagnose this noise for me

Postby Trackphotos » Mon Apr 13, 2015 6:18 pm

Been chasing this for a week or two.

Was not the loose number plate or loose tow hook bolt, removed the undertray and it did not get louder, removed the underbody bracing and it remained. Swapped brake rotors, pads, and pad retaining clips over from left to right, and the sound did not follow. Can easily hear in the clip when I'm on the brakes and hit a reflector, because the rattle is completely gone. I've tightened all the sway bar end links etc, still can't find the source.

QR Clubman: 1:03.9 | QR Sprint: 1:01.4 | QR National: 1:29.4 | LS: 1:01.5 | Mt Cotton: 51.6

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davekmoore
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Re: Diagnose this noise for me

Postby davekmoore » Mon Apr 13, 2015 11:35 pm

Sounds drivetrainy.
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)

Snowmotion
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Re: Diagnose this noise for me

Postby Snowmotion » Mon Apr 13, 2015 11:52 pm

I am not sure this is your problem but it may help with ideas (or not).

I had a screw fall out of one end of the alloy bar that sits under the glove box and at first it sounded like a suspension problem with a similar noise to yours.
As I said, not sure this is your problem but maybe. Good luck.
NB8A| WP 1:15.6 | SMP-S 1:08.56 | SMP-N 1:21.35
NC1| WP 1:09.42 | SMP-S 1:03.191 | SMP-N 1:16.1856 | SMP-GP 1:48.288

Trackphotos
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Posts: 1212
Joined: Tue Nov 06, 2012 10:03 pm
Vehicle: NB Roadster
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Re: Diagnose this noise for me

Postby Trackphotos » Thu Apr 16, 2015 10:13 am

Thanks for the suggestions guys, finally have an answer and confirmation that it's not unsafe.

In diagnosing I:
- Tightened number plate screws, were very loose
- Rotated brake rotors left to right
- Rotated brake pads and retaining clips left to right
- Removed tow hook (had one very loose bolt)
- Removed underbody bracing
- Removed undertray (no change in volume)
- Reinstalled OEM sway bars and end links
- Tightened every bolt I could reach under the car
- Checked for play in wheel hub and in driveshaft, no play in either

After all this without any changes at all, sending the video to Josh Coote resulted in the answer. Apparently a very small number of blue series shocks began to develop this rattle after a few thousand km of driving. Although it was about 51 weeks from when mine were installed to when the rattle started, it only did about 2500km in that time. Apparently one of the shims relaxes over time and begins to rattle when the shock changes direction. No safety concern, doesn't affect operation, just makes a rattling sound. Josh said it can be revalved to fix it, I'd just need to find time to get to Landsborough, so I'll see how much it annoys me now that I know what it is, and decide if it's worth fixing or not.
QR Clubman: 1:03.9 | QR Sprint: 1:01.4 | QR National: 1:29.4 | LS: 1:01.5 | Mt Cotton: 51.6


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