2002 A4 SE Avant Weird knocking noise at rear

[Tanuki]

I've never noticed it before but when in stop-start traffic, after rolling forward and then braking, there is a 2-3 second delay and then I hear this soft knock sound from the rear. Every move forward followed by a full stop I hear.

Doesn't sound like anything wrong really, but then what would I know?

Brakes work fine, actually car going great. Just hoping this isn't early warning for something.

BTW no, there is nothing in the boot rolling or moving around.

[diogenis]

Is it possible the sound you hear is the gas in your tank?

[Dave Avant]

Check the spare wheel well for an object but as above if you have more than a 3/4 tank of fuel it sloshes about making a dull thump sound.

I noticed this on mine!! Once near 1/2 tank and below, no noise.

If it was something like brakes or suspension orientated then it would do it more or less instantaneous.

[davelympany]

I've never noticed it before but when in stop-start traffic, after rolling forward and then braking, there is a 2-3 second delay and then I hear this soft knock sound from the rear. Every move forward followed by a full stop I hear.

Doesn't sound like anything wrong really, but then what would I know?

Brakes work fine, actually car going great. Just hoping this isn't early warning for something.

BTW no, there is nothing in the boot rolling or moving around.

hi there did you find hat the noise was, our A3 developed a strange knocking noise under rear floor...driving me crazy

dave