As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYDRAULIC CAUTION LIGHT ILLUMINATED AND PRESSURE INDICATED LOW AFTER EXTENDING LANDING GEAR. HYDRAULIC QUANTITY READS GOOD. FOLLOWING QRH PUMPING FLAPS DOWN. HAND PUMP WOULD NOT WORK, CAME IN WITH NO FLAPS. ON THE GROUND WENT TO OVERRIDE AND THE PRESSURE CAME UP AND STAYED. MAINTENANCE REPLACED MAIN HYDRAULIC RESEVOIR AND HYD PRESS MANIFOLD. EMERGENCY HAND PUMP OPERATES NORMALLY. EMERGENCY PRESSURE HOLDS NORMALLY.