As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED LOST RIGHT BRAKE AFTER LEAVING BLOCKS. PILOT SIDE, RIGHT BRAKE MASTER CYLINDER ORING LEAKING/BYPASSING HYDRAULIC FLUID. RIGHT BRAKE PISTO O-RINGS LEAKING. REPLACE O-RING SEAL IN THE PILOTS SIDE RIGHT BRAKE MASTER CYLINDER. REPLACED THE O-RING SEALS IN THE RIGHT BRAKE PISTON ASSEMBLY.