Front suspension knock

Jama665

Registered User
Hi all

So I got a hollow knock on the front nearside. Can't figure out where it's coming from.

Sounds like loose knock like arb hitting the subframe. So would seem easy to spot...

Had it on a ramp and everything is solid and looking spot on. Had wheel off can see anything obvious. It seems to disappear after it's been Jacked up but slowly comes back.

Only way to replicate it with the car not moving is on full left lock and bouncing the car on that corner, which is clearly audible Behind the wheel.

But for such a loose knock you'd think you'd be able to feel some play somewhere but nothing. It doesn't knock with every bump in the road either.

Cant figure it out. Anyone had anything similar and had a solution.

It's 2011 2.0tdi. Any help with this would be greatly appreciated. I'm pretty clued up so tried most the obvious things. But I'm new to tt's
 

PanamaS3

Registered User
does it happen over uneven road surfaces at fairly low speeds (ie. can hear it better)?
if so, try going over those roads where it does it and braking over the bumps....if you can't hear it then its the brakes....I have just discovered this on my car
 

Retroman

Audi A3 2010 Sportback 2.0 TDI 170 (CBBB engine)
The car's quite newish and assuming it hasn't done huge mileage, I'd be surprised if it was either a bush or anti-roll bar (ARB) component. In any event it's often difficult to reproduce an ARB problem simply by bouncing one corner of a static car. My internet guess is the coil spring. I've known coil springs break on new cars with virtually no mileage. Firstly, it's the left side which tends to get most pot-holes etc, it's intermittent and goes away temporarily after the shock absorber has been allowed to extend with the wheel jacked up. Often just a section of the bottom coil ring breaks away and falls out with drivers unaware until they have their MOT. IF broken, the ring will not be seated properly, putting it on full lock will disturb what seating there is and when driving, the shock absorber on that side may be having to work a bit harder and is as a result, banging against its "bump stop".

The giveaway is that the end of the broken coil is often sharp/jagged. Best of luck.
 

Jama665

Registered User
So it's 65k on the clock

Happens at low speeds generally.

Esp on speed bumps or left corners only when it's recoiling ie with the least load on the suspension in that corner.

I'll check both out. Thanks for the info
 

BillTheButcher

Registered User
I picked up an 8J TT RS at the weekend and it's got what sounds like the same issue. It only happens at very low speeds while turning the wheel (not necessarily full lock). I noticed it several times manoeuvring around a car park yesterday. It sounds like a ping pong ball rattling around.
 

BillTheButcher

Registered User
Have you checked the steering rack? I found these videos yesterday while rummaging through forums. Does yours sound like this?


 

Jama665

Registered User
Bit of an update.

Knocking is the coil spring knocking against it's seat, on the outer edge of the seat. It's still seated in the right place thought.

Not found the cause But suspect spring has cracked somewhere relieving some tension on the spring and not giving proper solid seat for the spring. Or top mounts bearings seized.
 

Retroman

Audi A3 2010 Sportback 2.0 TDI 170 (CBBB engine)
I’ve known the “tracking” being out of adjustment create a “knocking sensation” upon turning the steering on full lock or something approaching full lock. This can be accompanied by a “bump sensation” similar to driving over something like a broom handle. Sometimes the “tracking” being out of adjustment can also trigger an ABS warning light. A seized top mount would be most noticeable on turning as the seized bearing will tend to twist the top of the coil spring which will bang back into position when twisted so far.
 

Retroman

Audi A3 2010 Sportback 2.0 TDI 170 (CBBB engine)
I picked up an 8J TT RS at the weekend and it's got what sounds like the same issue. It only happens at very low speeds while turning the wheel (not necessarily full lock). I noticed it several times manoeuvring around a car park yesterday. It sounds like a ping pong ball rattling around.
I would start by getting the tracking checked
 

BillTheButcher

Registered User
I would start by getting the tracking checked
Wouldn't I get other symptoms if this were the problem? The car tracks dead straight and there's no vibration at all through the wheel. Also, it doesn't just happen at (or approaching) full lock. I get the noise when I turn the wheel even a couple of degrees either way.
 

Retroman

Audi A3 2010 Sportback 2.0 TDI 170 (CBBB engine)
Both those cars in the videos appear to be static and presumably not in gear and so the only things really moving (that would transmit those sort of "clicking" noises through the steering) are the steering mechanism e.g. rack and top mounts. Only my humble internet guess :shrug:
 
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