Front O/S strut / spring behaving badly.

Little Dog

Little Dog

A2OC Donor
European-Union
I say behaving badly but they appear to work fine over general rises and dips in the road and appear fine if I bounce the car by hand. The problem occurs if I drive over something a little more abrupt. The O/S bangs as if it has hit the bump stops and feels absolutely solid with very little movement. The N/S is fine in the same situation.
I'll get the front wheels off next time it's dry out there and take a closer look; any suggestions or experience of one side causing problems in this way?
Thank you.
 
Hi
You could try changing the drop links,these can course noise over uneven road surfaces if there worn.I do have one for sale if you wish to try this first

Pete
 
Thanks @P stamp but my drop links are new. The noise isn't a rattle or knock it is a full on bump stop hit bang! It's almost as if the strut seizes solid when expected to react quickly.

The N/S is fine over the same bumps.
 
Hi Phil

I don't know the answer but the attached thread shows some of the things others have tried.
My own car was cured by fitting Koni FSDs but I'd never attempted to isolate the problem to one particular side before the suspension change

https://www.a2oc.net/community/index.php?threads/ongoing-banging-suspension.20483/post-156556

Cheers Spike

PS - was planning a trip to John Bodys timber yard but just discovered it had been taken over, then the new owners went bust. Is that still the case or has it re opened under new management.
If convenient, was going to suggest I called to see you while in the area
 
@spike John Bodys closed and is now a housing estate. Shame; it was a good place to source specialist timber.

Thanks for the link too, it (and the further link within the thread) describe the problem I have perfectly. Unfortunately in my case the problem can't be short springs / low ride height as I have longer springs that are fitted with a factory tow bar.
 
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Sounds like the damper internal valving isn't working correctly - no easy way to test without a specialist damper test rig.

Simon.
 
Did wonder about that being a possibility @sco, so swap them left to right or replace them would be the way to diagnose that one?
 
Anything speed-sensitive suggest the internals of the damper to me (viscous resistance ∝ speed, and all that). Either that, or a rubber's packing up and allows something to clonk under the increased forces from the damper when it's generating a high resistance.
 
I'm beginning to think it must be the damper internals @Merlin3046. It's something that started after I hit an unmarked speed bump quite hard.

The problem is speed related, that is damper speed and not vehicle speed. At low driving speeds the damper bangs loudly if I drive over a small but abrupt variation in road height; pot hole / low curb etc. The only reservation I have is that this problem was not cured for another member with a full suspension rebuild; see link above in Spike's post. That said @spike did fix this problem with new dampers.

Something is broken; I'll find it.
 
sco said:
Other thing to check would be the top mount in case that has partially failed.

Simon.
Click to expand...

They creek in hot weather when turning the steering but are fine again now it is cool and wet. I don't think there could be sufficient play, they are clamped by the weight of the car to the car, to allow the boom! that I'm hearing.

However who knows? I have two top mounts in stock that I will fit when I tackle this one. That does mean if I fix the problem I will not know the cause of the problem :rolleyes:. Too many components replaced at the same time.
 
Life's too short to do the scientific search for the root cause. Replace all the bits that might contribute in one go and you won't lose sleep over what precisely was the problem. You'll be too pleased that it's fixed. Good luck with releasing that o/side top mount. I did that on Sunday and my hands are still covered in scrapes and bruises, and the engine bay was lightly covered with brake fluid by the time I'd finished.
 
@philward - if it's any consolation, mine was doing exactly what you describe when I first bought it. Are you running on the OEM dampers? Mine's still not back on the road so I don't know if I've fixed the problem for sure, but I'll be a bit peeved if it isn't as I've replaced just about everything where suspension is concerned.

The dampers on mine were the originals. They felt soft, as they had every right to after 17+ years of service. But just as you say, when I hit a particular, abrupt break in the road surface it felt like someone had replaced the dampers with solid iron bars, sending a shuddering thump through the cabin.
 
philward said:
They creek in hot weather when turning the steering but are fine again now it is cool and wet. I don't think there could be sufficient play, they are clamped by the weight of the car to the car, to allow the boom! that I'm hearing.
Click to expand...

That will be because there's no lubrication for the ball bearings in the top mounts. When you replace them, you will discover a collection of rusty ball bearings! Nothing to do with the boom though.

RAB
 
Good luck with this. Scientifically replace them then hit one then the other with a rubber mallet and see if you can replicate a difference in compression under forceful impetus.

Are all springs longer on a tow bar car or just the rears? I think I’d like longer springs and would like to know lengths etc. If there’s. Factory option for the TDi75 that’d be magical.

Ps. My car clonks, bumps, groans, scrapes and rubs over speed bumps no matter the speed. If that makes you feel any better?


Sent from my iPhone using Tapatalk
 
Pinkythelabrat said:
Are all springs longer on a tow bar car or just the rears? I think I’d like longer springs and would like to know lengths etc. If there’s. Factory option for the TDi75 that’d be magical.
Click to expand...

I dont know the answer to that one but I have promised to send the colour codes over to @Robin_Cox. I think he has the knowledge to advise, I just need to get under the car again.
What I can say is the rear springs are longer than standard giving a tall ride height at the rear. The front looks reasonably tall too so perhaps the front springs are longer as well?
There could be two monster truck look A2s in the not too distant future?
 
Thanks for the mention - I wouldn't say that I have "the knowledge". However, in response to a similar line of question I did end up collating what information on spring dimensions and approximate rate is available from the various aftermarket spring suppliers and attempted to correlate them with the OEM springs on various models of A2. The biggest complication is that Audi specified different springs when there were build subtleties such as OSS or not, tow bar or not, aircon vs no aircon with minor changes in spring rate and length (but no precise info except for the paint dots) and other optional extras rather than simple differences such as 1.2tdi vs 1.4i vs 1.4tdi, or sport vs non sport (+ / - ~30mm) - so there is a little more guesswork as to what will work. Bear in mind (from what I've picked up at A2oc and the 7zap diagram) also with heights that the sport and non sport use different rubber seats (and new vs worn could also impact on final height) at the top end of the rear spring and bump stops (123 vs 140mm) on the top of the rear shock so something as simple as replacing these with brand new ones of the correct or alternative height could potentially affect rear height without any change to the spring itself.

https://audi.7zap.com/en/rdw/audi+a2/a2/2003-248/5/511-511010/

parts 4 & 6 with alternatives.

It is possible to over-think this!
 
RAB said:
That will be because there's no lubrication for the ball bearings in the top mounts. When you replace them, you will discover a collection of rusty ball bearings! Nothing to do with the boom though.

RAB
Click to expand...
So should we lubricate them when replacing?
 
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