**** fix below didn't last, updated fix posted at end of thread ****
After 2 years of attempting to get Irvine BMW and Crevier BMW to diagnose and repair the sticky/clicky brake pedal on my F80 M3 but given a major run around by the service advisors and shop foremen, I finally took matters into my own hands.
I've read other posts about experiencing a random click when depressing the brake pedal while at speed, but couldn't find the solution online anywhere. Brought my car into dealer several times for what seemed like weeks at a time. Scheduled rides with the shop foreman a couple times only to show up and embarrassingly discover my car all taken apart in no condition to test drive (leaky intercooler replacement). These rides never happened. In fact nothing really ever happened except being told "it's normal".
But believe me, when your brake pedal randomly sticks a little in the up position every several minutes while driving, that's not normal!
I wound up bringing my car into a highly recommended shop owned by a former BMW Master Technician. He had the car for a few days and said he thought the brake booster or master cylinder was the culprit here and it was not a small job to swap these out. I was at the end of my rope with irritating brake pedal and fruitless dealerships.
Fixed the problem! No more clicky brake pedal at all!
I filed a case with BMW North America for reimbursement. MY CAR IS STILL UNDER WARRANTY with 33K miles. After several phone calls back and forth with a very nice representative I was told any sort of compensation was denied.
No specific reason.
It's pretty sad really.
Such a great car but not such a great company.