2016 A7 TDI - strange flapping noise when braking

[7DREW]

 

Before I purchased my 2016 A7 TDI it was exhibiting a strange popping noise when braking fairly hard at normal speeds (like coming into an intersection) in sequence to the speed of the car, so the dealership replaced the front brakes which appeared to have fixed it, after retesting it, but now its back and it sounds almost like flapping now. Any idea what it might be? 

[7DREW]

Thank you gentlemen, will do. But no thought to what it could be? ABS, caliper or? I ask because that is now *2 different mechanics unable to diagnose, and maybe I could help give suggestion/direction from you to them to figuring this out.

*(The 1st was the inspection I paid for before purchase by a foreign car mechanic shop, and the 2nd the LEXUS dealer who sold me the car after they replaced the pads.)

Edited September 5, 2023 by 7DREW

[Steve Q]

You'd think a loose caliper etc would have been picked up once brake were changed. 

Could it be a wheel bearing (even though this would be a rumbling sound normally) or a driveshaft issue? 

I'm assuming tyres have been checked too. 

[Magnet]

Thanks Drew,

My suspicion - but it can only be that - is that this is something fairly simple, and may be affected by braking, rather than caused by braking. 
Flapping noise:- loose plastic undershield ?? Complete guess, but….

Kind regards,

Gareth. 

[7DREW]

Thank you Steve & Gareth. Super grateful for your help. 

[7DREW]

Here's an update, but sadly no resolution yet:

Rotors and pads have been replaced, but the clicking/flapping is still there. I did however figure out a few things: It only occurs after brakes warm up, so I think something is loosening in the heat and therefore rubs/flaps against something every time the brakes are applied subsequent, and all but disappears again after a carwash which must cool the affected component.  Any ideas based on this new information ? Thanks in advance 😃

[Magnet]

Thanks Drew,

Have the brake disc shields been check - they usually rust badly and could become partially dislodged and flap about -? 
Just another guess! 
Can anything be felt at the pedal? 
Kind regards,

Gareth. 

[Stevey Y]

15 hours ago, 7DREW said:

Here's an update, but sadly no resolution yet:

Rotors and pads have been replaced, but the clicking/flapping is still there. I did however figure out a few things: It only occurs after brakes warm up, so I think something is loosening in the heat and therefore rubs/flaps against something every time the brakes are applied subsequent, and all but disappears again after a carwash which must cool the affected component.  Any ideas based on this new information ? Thanks in advance 😃

Hi could be a collapsing rubber hose holding the pressure so the pads are to close to the discs which would explain the fault not occurring when its been artificially cooled, I had it happen to me so I ended up replacing 1 calliper and both rubber hoses.

Steve.

[7DREW]

Yes, I thought maybe the brake disc shields also but they are in tact and not at all needing attention. I was actually shocked at how well they looked and felt. The rubber hose thing is interesting, do you have pics of the part you're referring to?