Bearing-type noise that isn't bearings

Any thoughts on this one please? The car is a 2000 model S8 (80k miles) and it has a rumble from the front end. It's quite bearable at cruising speed
but very noticeable at low speeds on good surfaces, where it appears as a "wop, wop" noise each wheel revolution. Front discs and pads are new, so I don't think it's a warped disc. Tyre wear is slightly uneven (more wear on the outside of the tyre on both sides) but no worse than on the front tyres of any Audi.
I suspected front wheel bearings, and last week I took it for service at a VAG main dealer (Crewe Audi - nee Charles Audi). I told them about the noise and said I suspected the bearings, but I told them they would need to test-drive the car and listen to it. As soon as I'd uttered my suspicions I regretted doing so, and guess what, they've just changed the bearings and the noise is still there. They obviously haven't listened for the noise either before or after doing the work.
Three questions. First, could this be worn inner or outer CV joints? Second, could it (gulp!) be from the final drive? Third, can anyone in the UK recommend a decent independent Audi specialist in the midlands who knows about quattros and is actually interested in diagnosing a problem, rather than just doing what the owner thinks might need doing? I was wondering about BR Motorsport in Leamington. I'm in Staffordshire.
Thanks for any help.
Regards
Jonathan Morton
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jonathan Morton wrote:

I'd check the rubber bushings in the front end. I had the same problem on my Audi 100 and could have sworn it was the front bearings. I had the shop check and they indeed indicated that it was the bearings, but they also noticed that the lower, inner rubber bushings on both sides of the front suspension lower arm was totally defective.
They wanted to replace both wheel bearings and the front shocks on a hunch, but didn't mention replacing the rubber bushings. Although that might have been obvious. Also, they wanted a hilarious sum for the job - around 1500 dollars.
I took the car for a second opinion. The other mechanic checked the bearings and said they were fine, but let's start with the cheap parts first - and I had the bushings replaced.
Noise gone.

Check the rubber bushings first, and see if they are gone bad.

Can't help you there. Sorry.
--
snipped-for-privacy@dod.no
------------------------------------------------------------------------
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
BBO wrote:

A friend with a TT had a similar grinding sound that was very noticable at low speed a few weeks ago. I drove it and usupected wheel bearings or inner CV. He asked if it could be tires. I said it could but didn't really think so.
A few days later he tried changing to his winter tires and sound was gone.
The offending tires were a fairly new set of Perellis (don't know the model or the spelling) with normal wear pattern.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I vote tires too move them to a different corner and see if the noise also moves you can do that! :-)
later, dave (One out of many daves)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Well, I'm going to try that in daylight this weekend. Meanwhile today I jacked up the car on one side and just turned the offending wheel. No obvious noise - which rather supports the tyre noise theory. But would a worn CV joint be expected to make a noise if not under load?
Thanks for the earlier feedback
Regards
Jonathan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I still feel the the tires might be your problem but Audi bearings can be noisy when going bad when under load but have almost no apparent symptoms when turned by hand while unloaded.
Not sure on the inner CVs. That was an opinion that was given to me by a very experienced Audi mechanic when discussing a similar problem on a friend's TT (the one with the tires causing the noise).
Jonathan Morton wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

noisy
turned
very
TT
Well I changed the front and rear tyres over and... the noise is duller and has moved to the back of the car. So it was the tyres.
On close inspection the one on the left (where the noise was coming from) had significantly uneven wear at different points round its circumference with one particular "flat spot" on the inner edge - though it was still legal.
I think I can be forgiven for not spotting this until I took the wheel off, but bearing in mind that the Audi dealer last week had the wheels off to do the bearings *and* purported to measure the tread depth on all four tyres as part of a "health check", I'm not exactly delighted.
Two new Contis have been ordered - and mortgage increased :-(
Thanks for all the earlier feedback.
Jonathan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Good to hear you found the problem. It does sound like my friend's TT problem. My son with his A4 2.8q Had the same thing a couple of months ago as well.
With that amount of irregular tread wear and noise it must have been broken cords and/or delamination which is a significant safety issue. I would have some words with the dealer about their missing it a week ago. The dealer issue tends to support my feeling that most of the techs at dealers now days can't diagnose anything unless the computer tells them the answer.
Might be worth asking the tire manufacturer to prorate replacements.
Tony

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

broken
have some

tends
diagnose
My thoughts entirely. It does hack me off that I'm a better technician than they are.

True, but it might not! These were Dunlops BTW, not some cheap brand. My local tyre stockist has had to order the new ones so I'm not having them fitted till next Saturday. I'll be very interested in their reaction. These are the remaining two tyres which were on the car when I bought it last year. I must say I'm always happier with used cars once I know that I put all the tyres on - you just don't know how badly the previous owner has treated them.
Regards
Jonathan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jonathan,
Please let me know how you fare. I have an A6 with similar sounding issues. Mine seems more of a vibration between 60 ~70 MPH. The dealership noted the problem and initiate a series of rebalancing of the tires to no avail. In sofar as to assist with tire replacement. Issue still there.
Bob
message

and
tyres
noise
I
Second,
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.