I've noticed that after driving forward and then stopping, backing up, and hitting the brakes again, they make a light but noticablle 'clunk sound. This only happens the first time you hit them. It seems like maybe the pads are shifting back a tiny bit in the calipers, or something more serious is loose.

Any ideas or insight?

 

I had a similar issue with my car. When backing up and hitting the brakes there was a loud clunk. The dealer couldn't figure it out. It took a small independent shop to figure out that it was a loose set of bolts . Can't recall where they were, but it's worth a shot. Sorry for the vague answer, but it's all I can recall.

 

That's a great clue. Thanks. So much for my loose pads theory.

I definitely want to get this squared away before hitting the track.

 

Joe had the same observation with his GT3: https://www.6speedonline.com/forums/...-i-backup.html

NO, he did not run over the neighbor's cat

I suspect it's the brake pads moving forward and back hitting the pad stops on the brake caliper. I heard the same thing when I switch from PCCB to steel rotors. No big deal. The "clunk" and "thump" are all gone after couple track events replaced by brain piercing squeals LOL

 

^ yep i had that problem. it just resolved itself... don't hear it anymore. i can't remember when was the last time i heard it but i haven't been running the oem pads for a long time now. never found smoking gun but it's very likely the pad shifting. i wouldn't worry too much about it.