As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 1828 - EN ROUTE ORD-YOW - SHORTLY AFTER TAKEOFF DETECTED LOW QUANTITY AND PRESSURE AT NR 2 HYDRAULICS SYSTEM. RETURNED ORD AND LANDED WITHOUT FURTHER INCIDENT. REPLACED NR 2 HYDRAULIC PUMP. NO LEAKS NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)