As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED RIGHT BRAKE PEDAL LOSES PRESSURE DURING TAXI. PRESSURE BLEEDS OFF CREATING A SOFT PEDAL. REPLACED O-RINGS ON LEFT BRAKE BLEEDER PORT, BLEED BRAKES, CHECKED BRAKE RESERVOIR AND LINES FOR LEAKS. CHECKED GOOD. PERFORMED CO-PILOTS SPONGY BRAKE CHECKLIST. EVERYTHING CHECKED GOOD IAW CESSNA MM 32-42-00.