Rattling noise from rear suspension.

[Eren S3]

Hey all

Car has developed an interesting noise from the rear left suspension. It sounds like a knock from the inside and a rattle on the outside. Recently changed all 4 corners to AP coilovers.

I've checked the obvious signs such as emptying the boot, taking out the boot liner etc, definitely nothing loose there. Also even checked the rear seats are firmly locked into place after being folded down. I've attached a video, you can hear the rattle as the camera is moved outside of the car. Car was recently serviced and the guys had a quick listen to it but 'required further investigation'. Just looking for suggestions or tips before I book it in with someone to look at it.

Any help is appreciated!

Thanks all.

 

[45bvtc]

That sounds familiar! There's a hard-plastic cup/cover sits at the top of the shock-absorber and for sure that came loose on my A1, re-fitted today (!) - and sounded very much as does yours - the cup/cover is loose push-in fit and is easy to displace when re-fitting the shock-absorber.

Just uncouple the top mount, compress the shock-absorber, re-fit the cup/cover - I added some clear silicon sealant to secure.

Hope this helps...

 

[Eren S3]

Thanks for the fast reply! I'll be over the moon if that is the same problem I have. I'll have to get it up in the air and have a little look. Could it cause a rattling noise as loud as it is though?! It's pretty obvious from inside and out.

My first worry was that the centre bolt on the shock absorber had come lose on the actual top mount...though I'm hoping I'd know about that if that was the case.

 

[45bvtc]

Thanks for the fast reply! I'll be over the moon if that is the same problem I have. I'll have to get it up in the air and have a little look. Could it cause a rattling noise as loud as it is though?! It's pretty obvious from inside and out.

My first worry was that the centre bolt on the shock absorber had come lose on the actual top mount...though I'm hoping I'd know about that if that was the case.

A1 MOT for me on Friday last, passed (Stafford Audi) and I changed my rear shocks back to KW Street Comfort on Saturday; immediate rattle/knock. Like you I stripped my boot and the noise remained, and from the offside-rear only! Fortunately I'd a spare set of shock-absorbers plus them hard-plastic cup/cover and sure enough when dropping the covers onto a hard surface they gave me the noise I was already experiencing in the car. So dropped the offside-rear shock-absorber today and sure enough the cup/cover was loose! Re-fitted the cup/cover and shock-absorber assembly and now all quiet!

Oh, and back on my summer rims and tyres, too.

What else can I say, good luck with yours...

 

[45bvtc]

My first worry was that the centre bolt on the shock absorber had come lose on the actual top mount...

If true the shock-absorber wouldn't be 'rattling' about, just loose in the up and down location. If, as mine, that hard plastic cup/cover is loose then for sure that'll be rattling/knocking about in the body-recess.

 

[Eren S3]

A1 MOT for me on Friday last, passed (Stafford Audi) and I changed my rear shocks back to KW Street Comfort on Saturday; immediate rattle/knock. Like you I stripped my boot and the noise remained, and from the offside-rear only! Fortunately I'd a spare set of shock-absorbers plus them hard-plastic cup/cover and sure enough when dropping the covers onto a hard surface they gave me the noise I was already experiencing in the car. So dropped the offside-rear shock-absorber today and sure enough the cup/cover was loose! Re-fitted the cup/cover and shock-absorber assembly and now all quiet!

Oh, and back on my summer rims and tyres, too.

What else can I say, good luck with yours...

Won't take me too long to raise the car and drop the shock at least so I'll give it a good check! Good to hear yours is all good now. I only hope for the same quiet! Well, quiet at least from the suspension

If true the shock-absorber wouldn't be 'rattling' about, just loose in the up and down location. If, as mine, that hard plastic cup/cover is loose then for sure that'll be rattling/knocking about in the body-recess.

Ooh yeah true, I did have a play around with the shock first time I heard this noise and when on the ground there was no play at all on the shock. I'll jack it up and check everything.

 

[The Cardinal]

Not sure whether it's the same issue, but the rear stone shields (if still present) are often the culprit on 8P1/2 A3s. Either removing them or jamming a bit of wood / polystyrene / something else between the shield and lower arm can help.

 

[Eren S3]

Not sure whether it's the same issue, but the rear stone shields (if still present) are often the culprit on 8P1/2 A3s. Either removing them or jamming a bit of wood / polystyrene / something else between the shield and lower arm can help.

Hey Ben, thanks for the reply. Forgot to add this in the initial post but those have been checked too, wasn't the issue as they've already been removed by the previous owner. Hoping for a break in the weather on a day off this week to check the shock itself and that cap as mentioned above. I'm hoping it's one of those noises that sounds worse than it actually is, it's holding me back buying new wheels...

 

[Eren S3]

Ok, another possible thing that had just been raised. Sounds like it could also be potentially a loose exhaust clamp as myself and a friend just had a little wiggle of the backbox and there is a remarkably similar sound. I know I needed to replace one of the exhaust clamps in the mid section which I have now ordered so I will also try that. Any other points to note now this sound has possible been located now?

 

[SootySport]

There’s a metal ring at the rear of the prop shaft that can comes loose and rattle around, easy to check that. Exbaust heatsheilds can also cause all sorts of noises, An MOT failure as well this year.

 

[springer]

For me it was a couple of bolts from the rear bumper diffuser that came loose. Diffuser became slightly loose and was knocking. Had bought the car from an auction with something like 'rear shock absorber may need replacing' remark only to find knock was actually coming from the diffuser.

 

[45bvtc]

And double-check that bottom shock-absorber bolt, make sure it's fastened tight - 80 to 115Nm; just had a similar issue on an Audi A2 and that darn bolt was just 'pinched'

 

[Nessy]

This won’t apply to the OP as he’s fitted rear coil overs recently, but thought I’d share a similar experience I had.
My car was making a metallic rattle/clunk every time the car went over a bump.
After checking there was nothing loose in the boot or spare wheel & toolkit I checked the rear stone shields....totally secure.
I did find the rear bumper diffuser slightly loose , so tightened a few screws, but this wasn’t the source of the noise.
After lying on the ground and thumping with the palm of my hand everything in sight I determined the source of the noise.
It was coming from the near side rear lower suspension arm .
Turned out that the very end of the top coil of the rear spring had broken off and had dropped into the spring seat pan of the lower arm and then slid into the hollow channel of said lower arm, where it merrily rattled and clonked away until discovery.

 

[Orange225]

Also the top of the damper corrodes and drops down, rattling on the shock shaft. Happened to mine, took weeks to work it out

 

[Eren S3]

Reviving the thread with a possible conclusion of the noise. After months of racking my brains and no one being able to find the noise, I gave the exhaust a few taps while it was up on stands and I think the rattling is coming from the bracket near the downpipe. I'll attach a link to a photo of what I think it is

https://www.akstuning.co.uk/exhausts/1135-genuine-tfsi-downpipe-brackethanger.html

Is this a one or two piece bracket here? I'm going to make sure it's all tight before I take it off or buy one in case it's just loose. Could this bracket be making as much noise as it is in the video??