Knocking on front wheels (Not ARB/Links)???

Foghorn

Foghorn

Member
Knocking on front wheels (Not ARB/Links) - RESULTED

This is now driving me nuts. I am getting the classic knocking sounds over bumps akin to a drop link ARB bush fault. However I have replaced all these, checked all suspension mounting, joints etc and still the knocking noise is there!!!

I'm thinking now CV/driveshaft problems? I have just recently noticed that on setting off at a sprint the ASR will flash and also going round a roundabout but NOT at the limit where the wheels lose grip/traction (I know what this feels like). Initially I thought a patch of diesel but now that it has happened more than once I'm thinking it's linked to the knocking. Car is on 75k

Anyone any clues?
 
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Chaps

In desperation to this problem I have undone the drop links and retightened them when there is (normal) load on the front suspension (somebody told me on another forum that this is how they should be tightened?). No difference.

I did notice that when the drop links were fitted they did not exactly line up with both holes and the joint had to be manipulated for it to pass through. My next plan will be to slacken off the ARB bushes, re-align the drop links and then tighten up the bushes. I'm tempted to just buy a new ARB but cant see any problem with the curent one.

I was also put onto the stabiliser link as a possible cause but cant immediately see where these go? Anyone any clues?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320652159616&ssPageName=STRK:MEWNX:IT
 
Sorry can't advise on the ARB/Droplinks, but perhaps it's the strut mounts, or the bump stops?
 
Foghorn said:
I was also put onto the stabiliser link as a possible cause but cant immediately see where these go? Anyone any clues?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320652159616&ssPageName=STRK:MEWNX:IT
Click to expand...

That part is the drop link, as used on the 1.2TDi - it is useless for our A2s.

For the record, I've had similar issues recently, but less of a knocking noise, more a rumble/grind - I've got some new drop links to put on this weekend, as well as new rear springs (as I broke one of the back ones).

I'm putting some of my issues down to the drive train (clutch/flywheel), but suspect my top mount bearings are shot too, and/or a CV joint is on its way out.

Cheers,

Mike
 
Mike - I'm more inclined to think the top mount bearings then as the characteristic noise for CV (going round corners/steering) are not there.

Is there a part # and schematic for the top mounts?

(If anyone has a 1.2Tdi and needs some links give me a call)
 
Top bearings are around £10 each and part number is 6N0 412 249C.

Changing them requires the removal of the entire McPherson strut assembly, spring clamps for dismantling of the unit and then re-assembly.

Cheers,

Mike
 
I'm now thinking more CV joint. Father in law changed one of his struts some time ago and still has the top mount section. Looking at that it is like a large metal washer with ball bearings in. Do you know if it is possible for that to move - consensus is that laterally it has nowhere to go?

I took the car for a spirited run down the country lanes this morning and on going in to a right hand bend at speed as the weight was thrown to the FNS wheel the traction control came on and I got a thumping sound!

The wheels had not reached the point of losing traction but it appears that when the FNS is put under heavy load cornering, traction control is coming on way too early in normal circs and today is the first time I have heard the thumping sound.

The knocking noise over bumps is just as bad. And there is no abnormal tyre wear or pull.
 
Mike - Did you resolve the issue with the drop links on your car? At present I'm inclined to go for the top mounts before the CV joint?
 
Not yet Brian - had the small matter of a new clutch and flywheel to sort out.

Mind you, I have fitted new drop links (the ones on were from the factory, so 93,000 miles old), but this hasn't made much change - top bearings are next on the agenda, when I get time.

Cheers,

Mike
 
Foghorn said:
I'm now thinking more CV joint. Father in law changed one of his struts some time ago and still has the top mount section. Looking at that it is like a large metal washer with ball bearings in. Do you know if it is possible for that to move - consensus is that laterally it has nowhere to go?

I took the car for a spirited run down the country lanes this morning and on going in to a right hand bend at speed as the weight was thrown to the FNS wheel the traction control came on and I got a thumping sound!

The wheels had not reached the point of losing traction but it appears that when the FNS is put under heavy load cornering, traction control is coming on way too early in normal circs and today is the first time I have heard the thumping sound.

The knocking noise over bumps is just as bad. And there is no abnormal tyre wear or pull.
Click to expand...

I have this problem too. The ESP kicks in when there really is no need to. It drives me nuts.

Since upgrading the suspension and lowering, its been no where near as bad but like you say on the FNS when the weight shifts to that corner the ESP cuts in, as the car obviously thinks the car is going to slide even though its not.

I too have a knocking in the suspension. Have got new droplinks and new top strut mounts from when I did suspesion upgrade yet still have it. I have new style ARB too so its not that either, which just leaves the CV joints as the culprits.

My driveshafts do look pretty worn out n rusting to high heaven so wouldnt surprise me.

Can one actually by inner and outer CV joint replacement kits??

John
 
John - good question and like you I think CV joints are the culprit but I was doubtful at first since there doens't seem to be any of the usual signs, grating on turning etc.

My next exploit was top mounts but now not sure.
 
OK Chaps. Spent most of Friday changing the top mount bearing. Despite the old one falling to pieces and ball bearings going everywhere the new one HAS MADE NO DIFFERENCE to the knocking noise.

I even swapped over the drop links from my 2004 A2 to mine to eliminate the possibility of the (new) drop links being knackered. Again no difference - the knocking noise is still present.

However I have had a thought. When I replaced my ARB bushes the roll bar looked to have been pushed over to one side as it had moved through the bushes (old style bar with plastic collars that move). I centralised it before replacing the bushes. When I looked at my 2004 A2 the ARB looks to be slightly offset - ie measuring the distance between the lower drop link hole and the inner wheel rim it is different on both sides.

So the question is, is it supposed to be offset and the fact I have centralised mine means that the ARB could be knocking on part of the engine/drive shafts/etc?
 
Well I think I have sussed the problem!

Last week I had the front on some ramps and went about banging all under the car. Despite the fact I have put new ARB rubbers on I noticed that when the FNS is under normal load (ie not jacked up) there is movement in the ARB!

Next job is to buy the upgraded ARB and new bushes and hopefully this will solve it. Also be interesting if this stops the ASR kicking in too early on right hand bends.

Watch this space - just need to find the time now
 
Finally!

Sorted out the knocking on the ARB. It turned out the 22mm bushes from Audi wont grip the bar hard enough and dont fill the saddle completely when it is butted up to the chassis.

I got hold of the 18mm VW stampe bushes (presumably the Polo ones). Whilst they wouldn't fit over the 'neck' on the collar, given the flaking of the plastic coating I was able to move the collar along and place the bush in the correct position so that I could bolt up the saddle. Believe me it was a tight fit but with some force managed to force the saddle over the rubber bush. Result no more knocking

Looking at the VW bush it has more shape to the flat base section so it fills the saddle fully when bolted up - a much better product!

Now to the ASR coming on during not excessive cornering. I've not tried this yet in terms of whether the movement of the ARB would cause it but my other thought is difference in front/rear wheel sizing?

I'm currently running standard 195/50/16 on the front but 205/50/16 on the rear - could a different size confuse the ASR to beleive the wheels are rotating at a different speed hence it correcting it?
 
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