Hi guys. First and foremost thank you for taking the time to read my issue. For about 6 months the car sounds like a bag of spanners while in motion. It's a tinny noise like heat shield or another thin metal. I've had all the exhaust heat shields off and repaired or replaced them and still rattling. My dad made a good point by saying does it happen when you press the brake and the answer is no. So I stripped all 4 calipers cleaned, greased checked for wear on sliders and everything seemed ok. Put it all back together and I'm still no wiser. A friend said pack the sliders with copper grease. Have any of you guys had anything similar to this happen. I did read most of the previous forum lists to see if I could find anyone with a similar issue but to no avail. Any help or advice would be really appreciated. I've had this car up on the ramps or axle stands so often it's becoming a local joke 🙄

Im a first time poster so incase it doesn't mention it, the car is an 07 A4 S Line B7 Avant. Thank you. 

Welcome Colin and sorry to hear of your issue. 
Brakes - not sure of the logic to associate this with the brake calipers, but when you were dealing with this, did you inspect all brake disc backing plates? 
These are prone to rusting and bits scraping on the discs etc. Incidentally, silicone grease is normally recommended for sliders and not copper grease. 

However, by your description it doesn’t sound like that, but worth a coat of inspection.

Re. noise:- is it evident where the car is stationary with the engine running, or only when the car is on the move? If the latter, ( assuming manual) knock it out of gear and see it it affects the noise when coasting. 
Regards,

Gareth. 

Thank you for your response Gareth. I only hear it when going over bumps or pot holes. I never thought to try it in neutral and I'll take on board what you say about silicone for the sliders rather than copper. The backing plates are solid but that's the kind of metallic sound that I am hearing and it's the first thing I checked after repairing the exhaust heat shields. I'll get on what you've recommended this weekend and respond straight away. Thankyou again ❤

Colin.

Have you inspected the brake pedal and master cylinder mounting? Noises from either of those would stop when pressing the pedal.

That's a fair point Cliff. I'll look into doing that this weekend. Thank you for you input. 

10 hours ago, Colin. M said:

Thank you for your response Gareth. I only hear it when going over bumps or pot holes. I never thought to try it in neutral and I'll take on board what you say about silicone for the sliders rather than copper. The backing plates are solid but that's the kind of metallic sound that I am hearing and it's the first thing I checked after repairing the exhaust heat shields. I'll get on what you've recommended this weekend and respond straight away. Thankyou again ❤

I've tried it in neutral but the rattle noise still rattles and is silenced as soon as I put the slightest weight on the brake pedal whether in neutral or in gear. Thanks