Firmer suspension but rumbling sounds :(

Alan_uk

Alan_uk

A2OC Donor
NOW DIAGNOSED - SEE POST https://www.a2oc.net/community/inde...pension-but-rumbling-sounds.39369/post-361035

Some years back I had the front and back suspension overhauled: new springs (Lesjofors), shocks (Monroe) and bump stops. Had an MOT immediately afterwards and every year since, all OK.

Since then I've had a rumbling noise when going over bumps. It seems to be getting worse (maybe partly the roads are getting worse).

Today I took everything out the back including some trim:

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Took it for a spin and the noise is still there. I made a 4.5mins recording here: https://www.dropbox.com/s/q1kyntvs93y9dql/Audi A2 Sound Recording 2019-04-18.m4a?dl=0

(Hey! just discovered Dropbox shows an audio graph and you can see the rumbling noises as jumps in the graph)

0:00 starting and 20 mph zone going over 4 anti-speed cushions;
1:00 along a faily smooth road up to 30 mph with odd patches and manholes
1.30 reverse at roundabout and back along same road
2:20 20 mph residential area with anti-speed humps/ramps and odd manholes/patches
3:00 leave 20 mph zone
4:00 arrive back at house; reversing bleeps

Everything is firm in the boot.

I'm thinking it may be the exhaust. It's the orginal 15 years old, so some the rubber mounts may have perished though the tail pipe is very firm. Not feeling well enough to getting under the car.

Due for an MOT soon so I could get the garage to check unless anyone else has ideas I could check?

What about those A2 owners who have gone for firmer suspension - is it noiser?
 
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Heat shield possibly insecure
Or exhaust against fuel tank?

If your on friendly terms with your Mot tester he may let u have a look while on the ramp?
 
I did fix the heatshields 2 years ago, post the noise, but more fasteners could have gone since then. The shields are so flimsy I don't think they would make much noise.

It's an Audi Independent. Seem friendly but there is always H&S. I could turn up with all my PPE! When I booked the MOT today and mentioned the sound they said if the exhaust was broken they would report it on the MOT, to which I replied that they had MOT it since the noise started. But as you suggest it may be hitting without any mounts broken. Heeds a good shake while on the ramps.

I'll see if I can get the energy to get under the car. If it is hitting the tank then I would expect some marks

Thanks for your suggestions.
 
Andrew said:
That's a flapping sound. Wheel arch liners? - Andy
Click to expand...

Do you mean loose? Well I had the bumper sprayed last autumn and the bumper was removed and I think this involves the liners. Maybe that's went it go worse. I'll have a look.

I measured the ride height before and after the suspension overhaul and it was almost the same.

Thanks for your suggestion.
 
Alan_uk said:
Do you mean loose? Well I had the bumper sprayed last autumn and the bumper was removed and I think this involves the liners. Maybe that's went it go worse. I'll have a look.

I measured the ride height before and after the suspension overhaul and it was almost the same.

Thanks for your suggestion.
Click to expand...
Finding the source of a sound that should not be there on a car I find next to impossible, sound travels/reverberates masking its source. I have had several over the years and every time I got the origin completely wrong.

Yes I mean loose, it reminded me of a loose wheel liner I had I could only hear it when driving at low revs, in normal driving the engine noise drowned it. It struck me that when your rear shock absorbers were installed they probably removed the arch liners to access the top bolts and if they punched in the expanding pins too far in the top plastic retaining wheel arch liner rivets they are impossible to retrieve and maybe just put back without the expanding pin.
Check all rear arch lining fixings are correct. Just a wild guess.

You really need to get a good look at the underneath.

Andy
 
Thanks Andy. I pushed the wheel arch liners as best I could and felt no movement. I do plan soon to take the wheels off to give them a good clean and will then be able to inspect the liners better. Meanwhile I hope to get the car up on my ramps tomorrow to have a good look / push and pull on heatshields and exhaust.
 
Sounds plastic to me.
I have a rear boot spoiler that vibrates.
Is the boot tight ?
OSS glass jumping over bumps?
That's all I can think off. Good luck.
 
Thanks Clemy.

> I have a rear boot spoiler that vibrates.
Really! They seem pretty well fixed on. I'll give it a shake and hope I don't break it!

> Is the boot tight ?
I thought of this as I can slighty move it if I sit in the boot and grap the handle for closing the tailgate. Is the lock catch adjustable?

> OSS glass jumping over bumps?
Don't have OSS unfortunately
 
Yesterday I got under the A2.

All fasterners present on the heatshield though there seems one that was never used. Can't add a new fastener there as it's the fuel tank.

I found 4 places where there is a gap between fasteners and potential for the sheild to rub against the body. I placed 4 peices of 1/2 inch rubber sealing strip between the shield and the body, but on a test drive this made no difference.

Not able to see the heatshield above the exhaust and test if it could move and knock, but in general the shield seems pretty firm.

All exhaust fixtures present. I can wobble the exhaust but there is no knocking against the body/frame.

Today put the rear seats, false floor and parcel shelf back and it helps a bit to reduce the noise. Trouble is, I'm now listening for it still.

Booked in for MOT on 2nd May and they will have a look under.
 
Also worth checking when you have the wheels off the shock absorber upper covers. The tend to come adrift and drop down the shock where they rattle. Not a MOT failure just an advisory. They are plastic held onto the bump stop by a flimsy metal ring, either rubber shrinks or ring breaks and the cover drops. Here is a picture of common way to fix without taking shocks off the car.

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not an A2 but same process.
Another problem I have had it the rear crash beam can vibrate. Give the bumper a sharp bang just below the rear lights on both sides if it rattles bumper off to fix with bolts and now washers.
 
Thanks for this hints audifan Can't hit the bumper as it's got fresh paint on it but I could remove the trim above it and then test it for firmness.

I'll check the shock absorber upper covers but I recall they were both OK - easy to check again.
 
You can slap it hard with the palm of your hand.. Oh Er Missus. That should be enough to shock the crash beam and if the mounts are loose or worn it will vibrate.
 
Alan_uk said:
Thanks Clemy.

> I have a rear boot spoiler that vibrates.
Really! They seem pretty well fixed on. I'll give it a shake and hope I don't break it!

> Is the boot tight ?
I thought of this as I can slighty move it if I sit in the boot and grap the handle for closing the tailgate. Is the lock catch adjustable?

> OSS glass jumping over bumps?
Don't have OSS unfortunately
Click to expand...
50625
Adjust these maybe, if boot has play in it.
 
I started hearing a rattling from my nsr shock ages ago , I had to get the shock changed before the mot recently as it was leaking despite being a year old , after it was changed I mentioned the rattle to my mechanic who said it could have been the faulty shock , but the rattle has gotten worse over the past week and is doing my head in , it’s going on the ramp this Saturday morning for further investigation


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Sorry to hear of your woes hadi. Agree, it does irritate - I can't stop listening for my own noise.

Had MOT today. All fine. They had a good look underneath and couldn't find anything amiss. They didn't have time for a road test. They suggested they could do that at a service, but that's a year off. They said noises are difficult to find - I'm thinking cha-ching cha-ching !

I've been very busy this week but come next week will look at the tailgate door catch suggestion. I did mention that I could move the tailgate door from inside the vehicle, but I checked outside and there is no movement, so I'm thinking I was just moving the trim panel.
 
Alan_uk said:
Sorry to hear of your woes hadi. Agree, it does irritate - I can't stop listening for my own noise.

Had MOT today. All fine. They had a good look underneath and couldn't find anything amiss. They didn't have time for a road test. They suggested they could do that at a service, but that's a year off. They said noises are difficult to find - I'm thinking cha-ching cha-ching !

I've been very busy this week but come next week will look at the tailgate door catch suggestion. I did mention that I could move the tailgate door from inside the vehicle, but I checked outside and there is no movement, so I'm thinking I was just moving the trim panel.
Click to expand...

Not long back from the guy the sorts my A2 , after putting it up on the ramp he examined the nsr wheel and upon lifting it up with his arms he found the noise ,at the top of the shock there is an alloy fitting which the top thread of shock goes through and is secured by a nut , this was loose and has been tightened up and the noise has gone , hope this helps you in sorting out your noise


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hadi said:
Not long back from the guy the sorts my A2 , after putting it up on the ramp he examined the nsr wheel and upon lifting it up with his arms he found the noise ,at the top of the shock there is an alloy fitting which the top thread of shock goes through and is secured by a nut , this was loose and has been tightened up and the noise has gone , hope this helps you in sorting out your noise
Click to expand...
Thanks hadi. Yes that nut has crossed my mind. I guess it's a case of removing the trim over the rear arches to get at it. I will see if I can find a guide under the "How to". Also need to find the torque setting.
 
Alan_uk said:
Thanks hadi. Yes that nut has crossed my mind. I guess it's a case of removing the trim over the rear arches to get at it. I will see if I can find a guide under the "How to". Also need to find the torque setting.
Click to expand...

They guy that done mine took the shocker out and done it in the vice , an easier way of accessing the top of the shocker is to make the hole in the trim bigger to get access


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