A4 B5 2.6 Quattro...odd knocking noise???

Audi Nut Joined: Jul 06, 2011 Posts: 69

Hi all,

I know it is impossible to diagnose a fault such as this without hearing it, but thought it would be worth asking, you never know Smile

I have an odd knocking from my near side rear wheel. It sounds rotational, and increases with speed. Sounds at its worst accelerating at around 30 - 40mph

It almost sounds a bit wooden, not like a metal crunching, but a wooden knocking. Whilst driving, it can come and go - I went over a bump this morning and it stopped for a few minutes...

If I am accelerating it is there, and then as I declutch to change gear, or decelerate, it is quiet...comes back after decelerating down to about 40, stays there, sometimes goes...very frustrating!!!

Any clues or hints would be very welcome - I will get it up in the air tomorrow on my day off and see if I can find anything...I am assuming it's not on the wheel, as it would be there all the time if it was...hate things like this!
thanks in advance for any help - alternatively if anyone wants a quattro with a brilliant engine for parts, give me a shout - my commute has changed and I could do with a diesel now, typical that the audi has chosen now to play up!!!

Inexperienced Joined: Jan 14, 2012 Posts: 23

Just take it to service. Moust of them will tell you whats wrong whit it for free and maybe even straight away. After that you can fix it or just leave it there if you dont want to do it.
Does it change when you go around corners/steering or only when you depress the clutch pedal?

Audi Nut Joined: Jul 06, 2011 Posts: 69

Not many places I know offer free diagnosis...

it does seem worse on right hand bends

Inexperienced Joined: Jan 14, 2012 Posts: 23

Sounds more like drive shaft,wheel bearing but these squeek or control arms very very old or any bushing.

Audi Nut Joined: Jul 06, 2011 Posts: 69

I've only known bearings to "drone", this has gone straight to "knock like a mad thing" Smile

I'll check the control arms and drop links etc tomorrow, good point, thanks Very Happy

Posted: Thu Jan 19, 2012 10:06 pm

Rear ARB bush or drop link. The drop links are hoor'n expensive from main dealer. Don't think you can source after-market links for the rear either.

Audi Nut Joined: Jul 06, 2011 Posts: 69

I jacked it up yesterday, and took the NSR wheel off, far too tight those wheel bolts!
Inside edge of the tyre is very bald...pointed me to tracking...
Could not find any play in any of the arms, bushes etc...did seem to be a bit noisy when turning the hub, but really not sure - the car has done 225k miles, so I don't expect the running gear to be silent...

anyway, I gave up, and drove the 8 miles from my workshop home...not a peep...I am even more confused now!

Audi Nut Joined: Dec 16, 2010 Posts: 87

Hi mate I've got the same car are you sure it's nothing to do with the rear diff maybe seals have gone and diff is running dry, I know these seals go quite often and maybe just a thought you might want to change your 225 000 miles and still going strong to 225 000 miles and weird noises have started lol only joking, good luck mate hope you sort it.

Audi Nut Joined: Jul 06, 2011 Posts: 69

yeah...maybe the sig does need a small change Smile

I do think the diff might be the fault, I couldn't see any signs of fluid anywhere though, the diff and surrounding area is all dry...I couldn't see the oil filler location on the diff, so any pointers there would be a great help...something to check next weekend methinks Smile

Audi Nut Joined: Dec 16, 2010 Posts: 87

Worth a go, the filler plug is a 10mm allen key and it's located on the passenger side just behind the cv joint, I'll try to find a link for you but it's pretty straight forward to do, hope that helps mate

Audi Nut Joined: Dec 16, 2010 Posts: 87

Here's a link I found it's got pics aswell http://audi-diy.blogspot.com/2007/10/audi-a4-b5-rear-differential-oil-change.html

Audi Nut Joined: Jul 06, 2011 Posts: 69

That's excellent, thanks mate Smile

I drove the 25 mile journey to work this morning...and it stayed pretty quiet, just the odd little squeak when I was nearly there. Almost sounded like a squeaky shock or rubber...whatever it is, it is quiter since I jacked it up, took the wheel off, wiggled the arms and joints, rotated the hubs to and fro...put the wheel back on and put it back on the ground.
Now I am even more confused Laughing

Audi Nut Joined: Dec 16, 2010 Posts: 87

Try spraying abit of wd40 on all the rubbers joints ect see if that stops it, at least then you will know before you go out and spend shed loads of cash on trying to find the problem

Audi Nut Joined: Jul 06, 2011 Posts: 69

Yes, I'll give that a go. I intend to get underneath and change the diff oil, so I'll give the bushes a squirt while I'm there.

I was trying to look at the shock top mount, but it's all hidden away - does the plate that holds the top arm come away leaving the shock in place? The top mount is about the only part I can't see from under the car, could be an obvious fault that I am missing...

Posted: Mon Jan 23, 2012 9:11 pm

The rear diff takes a couple of litres. Best to get the car up to operating temperature so the oil is a little thinner prior to draining. Just ensure you can access the filler plug before pulling the drain plug! Rolling Eyes

The drive-shaft seals can leak, however you've mentioned there's not wet patches on the diff, so I'm sure it's fine.

One other thought - if it is suspension related, then check the strut isn't leaking, or the coil-spring end hasn't lost a couple of inches at the end. This is a useful thread, if nothing more - than for pictures to disassemble. While you're under the car - check the rear CV boots aren't torn - could even be a shot CV joint, although I think that's unlikely. http://www.a4mods.com/index.php?page=webcontent/pages/coilovers.html

Audi Nut Joined: Jul 06, 2011 Posts: 69

Wow, what a different set up - separate springs, same as my 1984 RX7 Laughing

I checked all the boots, and bushes, couldn't see anything...

I drove 50 miles yesterday without fault...then on my last short journey home the noise started again, going round a roundabout, then it was back to stay once more.
I'll be back underneath it at the weekend, see if I can find anything...

Audi Nut Joined: Jul 06, 2011 Posts: 69

Well, I am afraid to say, this has me beat Sad

My better half and I have discussed it, and we feel it best to give in, before we spend a wad of cash on it, and still not fix it...so it's on ebay

http://www.ebay.co.uk/itm/290665491709?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

if anyone from here wants it, email me at marcrs at live dot com

Take it this weekend, 5 months tax and MOT for £400 Smile

Posted: Thu Feb 02, 2012 7:09 pm

It's good that your ad sounds honest. A good point for a seller on Ebay..!

Best of luck with the sale. Whatcha getting next??

Audi Nut Joined: Jul 06, 2011 Posts: 69

Thank you - I am always as open and honest as possible, pity there are so many out there that hide faults, or deny knowledge of them...

I'm picking up another Mazda 323 on Friday, I have a couple of Mazdas, the 323 and the RX7...I'll have to get used to the build quality...nothing like the Audi!!!

I'll have another one day...but it'll be an A4 or A6 diesel Smile

Inexperienced Joined: Jan 14, 2012 Posts: 23

This looks like an good chance to break another audi Smile

Cheap buy for the track for a good fun.

Audi Nut Joined: Dec 16, 2010 Posts: 87

Hi mate sorry you couldn't sort it hope it goes to good home and not the scrappie, I see your near Eastbourne ?? I live in Eastbourne lol

Audi Nut Joined: Jul 06, 2011 Posts: 69

Thanks mate, yeah, I'm sorry too, but I have to draw the line somewhere - realistically I couldn't afford to commute in it now, and it wouldn't be worth that much more if I fix the knocking - could be a £20 fix, but could be a few hundred??? Sad

My workshop is up on the A22 (details are on my website - www.paragonautofinishing.co.uk ) - feel free to pop up one weekend - I have a silver A6 allroad in this weekend for a 2 day paint detail...hope if fits in the bay Laughing

Audi Nut Joined: Dec 16, 2010 Posts: 87

That's exactly the point where do you draw the line?? I know exactly where you are I drive by you all the time as I use the fish shop in the garden centre right next to you for all my marine fish bits and bobs( sad I know lol) I might just pop in one weekend and take a look, allways good to know a good detailer, I've got my own high speed buffer but been to scared to use it lol,

Audi Nut Joined: Jul 06, 2011 Posts: 69

Nice one, be good to meet you Smile

Don't be scared, just be careful Very Happy

If it's a rotary machine, be very careful, if it's a Dual Action then it is safer, but you can still get it wrong...
If you ever need any tips or advice, give me a shout mate Smile

Audi Nut Joined: Dec 16, 2010 Posts: 87

Ok mate thanks alot, it's a rotary unfortionatly, I did want a DA but the missus got me it for Xmas. Will pop in at some point, it must be you I see in the black rx7 with the spoiler driving around sometimes, very rare cars to see these days, I allways say to the missus if we didn't have kids....... Lol

Audi Nut Joined: Jul 06, 2011 Posts: 69

Not me in the black one, my RX7 is tucked away in the workshop awaiting arches and a paint job - it's a 1984 1st Gen...

My kids moved away with my ex...so now I have an RX7 Laughing

Audi Nut Joined: Dec 16, 2010 Posts: 87

Oh ok lol the black one that I see is a newer one, rounder shape.