Loud repetitive thumping from rear under heavy braking

[wootloops]

I have a 2008 E92 M3 that I recently purchased about 3 weeks ago. The car has around 56,000 miles. Suspension-wise, it's relatively stock other than B&G lowering springs.

Under heavy braking, there is a loud thumping sound coming from the rear end of the car. It's not just one thump, but multiple that seem to last as long as you are under heavy braking.

I had the car in the shop this week for rod bearings, and the mechanic was the one who noticed this before I did. Before I picked the car up, he said he took a quick look in the rear and could not see anything obvious. I didn't have him dig into it further because I needed to pick the car up today.


Has anyone experienced a repetitive thumping/clunking sound from the rear or have any idea what it may be? It does not happen under light braking, only moderate/heavy braking... maybe 75% of the pressure you would need to trigger ABS. And no, it does not feel anything like ABS going off.

Thanks in advance.

[wootloops]

Here is a video ... It only made a single "thump" on this one. I was hard braking from ~60mph down to ~10mph.

This is the same sound it has been making, but in other cases it would be 2-3 thumps in repetition and not just one.

[StripclubDJ]

Only time I've ever had that happen , a rear rotor was cracked in half