A Rear Rattle that'll drive you mad.

[roadvoyager1]

Since changing the rear dampers, top mounts, ARB bushes and drop links recently I have a rattle/noise. Not the same as you recorded but just as irritating. Like yours it is not present with the roof down (or at least I cannot hear it).

A week or so after the new dampers and top mounts were fitted I checked the fixing bolt on the damper shaft and found that the reinforcement washer had very slight movement, I tightened it maybe an eighth of a turn and it was solid. This seemed to cure it for a couple of days, then it came back. I presume that the top mounts had settled very slightly allowing the washer to move.

The new bushes and drop links were fitted with a bush lube but there is a bit of a creak on the drivers side. It seems that the new parts have changed the dynamics of the rear suspension and bought out problem that was being masked by the old set up.

Today, in addition to checking handbrake cables etc, we applied some bush lube to the bushes that were not replaced (not sure if it will penetrate at all) and to the spring pads in the latest attempt to get rid of the offending noise. Unfortunately it was raining and the effectiveness of these measures will have to wait until another day.

Keep us all informed as your investigation progresses as it seems you are not the only one with this type of concern. Good luck.

 

[Faheem]

@roadvoyager1 I'll definitely keep you posted pal.

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Update: today I removed everything from the toolkit in the boot, and I cleaned the boot out completely. Put my phone on record and took it for a drive and I can still hear the rattle, if anything it was louder in the boot. This means that the rattle isn't coming from inside the cabin but rather from under the car. Next job is to remove the bumper tomorrow morning (weather permitting) and see how those weights are doing.

 

[Low Rider]

I've got an exhaust bracket that's lose that needs sorting out tomorrow

 

[Dino D]

Has anybody mentioned the diff bush yet? That was the cause on mine.

 

[Faheem]

I've got an exhaust bracket that's lose that needs sorting out tomorrow

Have you seen the forecast tomorrow? ..you've probably got a garage though

Has anybody mentioned the diff bush yet? That was the cause on mine.

I'll take a look at that before removing the bumper. Cheers

 

[Low Rider]

No Faheem I wish I had.
I'll just take it to an exhaust company

 

[Redline]

The rear of the car is corner weighted with some metal weights behind the bumper
View attachment 39625
It could be one of these ?

What are these weights for? Seems odd adding weight to a car for no good reason.

 

[andyglym]

There seems to be a trend here, I get an annoying noise over and behind my right shoulder but only when the roof is up. Frankly it's beyond me as I've looked and lubed everything that I can see. Don't drive much with the roof up so it'll just have to stay.

 

[Dino D]

What are these weights for? Seems odd adding weight to a car for no good reason.

BMW call it a vibration damper
http://www.realoem.com/bmw/enUS/sho...-1998-Z3-BMW-Z3_28&diagId=51_2331#51128399319

 

[Dino D]

There seems to be a trend here, I get an annoying noise over and behind my right shoulder but only when the roof is up. Frankly it's beyond me as I've looked and lubed everything that I can see. Don't drive much with the roof up so it'll just have to stay.

I'll put a fiver on it being the diff bush - I looked everywhere and was certain it was the fuel tank but it was the diff bush. Looks ok when in situ but is guaranteed to be degraded at this age.

 

[andyglym]

I'll put a fiver on it being the diff bush - I looked everywhere and was certain it was the fuel tank but it was the diff bush. Looks ok when in situ but is guaranteed to be degraded at this age.

Hopefully mate and thanks. Saving up for diff bush, shocks and springs so hopefully will cure it.

 

[Bozzy]

I'll put a fiver on it being the diff bush - I looked everywhere and was certain it was the fuel tank but it was the diff bush. Looks ok when in situ but is guaranteed to be degraded at this age.

I replaced my diff mount bush with a poly one and the rattle is still there Dino unfortunately,again only when the roof's up .

Steve

 

[andyglym]

I replaced my diff mount bush with a poly one and the rattle is still there Dino unfortunately,again only when the roof's up .

Steve

bugger

 

[Bozzy]

b*****

Sorry Andy .

Steve

 

[andyglym]

Sorry Andy .

Steve

No dramas mate, the old girl is 19 next month so the diff bush is probably on its last legs anyway

 

[Bozzy]

No dramas mate, the old girl is 19 next month so the diff bush is probably on its last legs anyway

That's what I thought before I changed mine,but it was actually in good shape tbh and it wasn't easy to dislodge it when most people have said there's almost fell out. BUT it has made a huge improvement in gear changes,much smoother and quieter so well worth doing mate .

Steve

 

[EnthuZiaZT]

I had an annoying little rattle on one of my cars, turned out a mechanic had rested a socket on a handy ledge underneath the car and forgot it. When I put my hand up into the same area I found the socket. I still have it somewhere.

Mike

 

[Faheem]

Looks like I've found my problem (I think)

View: https://youtu.be/sYJje3f7mnQ

View: https://youtu.be/M8YKyaGMWi4


I secured the bracket to the fuel tank on the drivers side a few days ago, however, after a thorough investigation today it still seems to be rattling on the near side, I was able to retrieve this piece of rubber that was hanging lose on the nearside bracket

One thing I'm still struggling to understand is why I can't hear the noise with the roof down and why the noise can be heard from inside the boot.

The good news is that my subframe seems intact for now and I also checked the weights in the rear bumper and I found them to be okay - I did this by removing my spare tyre and going underneath the car and wiggling the weights, because I have small hands I did this without ripping my hand open.

 

[Low Rider]

Excellent let's hope you've found the problem Faheem. I guess the reason you are unable to hear the noise with the roof down is because the road and wind noice drowns the sound of your rattle out

 

[Antm72]

Also the waddng and the weight of the roof folded would probably dampen the sound ...add the wind and road noise and as said you can not hear it