As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOTICED A STEADY LOSS OF 'B' SYSTEM HYDRAULIC QUANTITY AFTER REACHING CRUISE. TRIED TO ISOLATE SYSTEMS AND WHEN TURNING OFF THE 'B' SYSTEM SPOILER SWITCH QUANTITY STABILIZED AT 39 PERCENT. REPLACED THE SEAL PLATE BETWEEN THE TRAILING EDGE FLAP CONTROL VALVE AND THE FLAP LOAD LIMITER SOLENOID VALVE. REFERENCE BOEING SERVICE LETTER 737-SL-27-104.