As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURN BAC, DECLARED EMERGENCY MASTER CAUTION AND "B" HYDRAULIC SYSTEM LOW PRESSURE LIGHT ILLUMINATED FOLLOWED BY "B" HYDRAULIC SYSTEM QUANTITY GAUGE DROPPING. REMOVED AND REPLACED HYDRAULIC LINE AT "B" SYSTEM ACOUSTIC FILTER AND "B" SYSTEM CASE DRAIN FILTER PER MM.