When I'm braking after landing, I've noticed a pronounced shudder comming from my left brake assembly that shakes the whole airplane when I get below about 28kts IAS. I took apart the assembly and found that my disc is slightly warped and I know exactly why. I was unwise in breakin in the new brakes right after a rainfall that left the taxiway wet. Water on piping hot discs is bad and now I'm paying for it. $87 to be exact. New disc coming soon :)