As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 4781 - WHILE TAXIING TO THE GATE, THE HYDRAULIC PRESSURE INDICATOR WHEN TO 0 PSI. AIRCRAFT CAME TO A STOP AND PASSENGERS DEPLANED. MAINTENANCE FOUND NR 2 BRAKE HYDRAULIC LINE SWIVEL HAD FAILED. LINE WAS REPLACED AND AIRCRAFT WAS RETURNED TO SERVICE. (M)