As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: BRAKES ARE VERY WEAK (SOFT) AND THEN BITE AT LONGER THAN NORMAL PRESSURE. MAINTENANCE FOUND THE ALTERNATE BRAKE RESERVOIR WAS LOOSING PRESSURE AND WAS REPLACED PER AMM 32-43-11. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED.