What was found
HYDRAULIC SYSTEM B PRESSURE SLOWLY INCREASED FROM 3030 PSI TO 3480 PSI OVER A 3 HR. PERIOD AT CRUISE FL 370. GROUNDED - YES. REMOVED AND REPLACED #2 ENG HYD PUMP REF B737-800 AMM 29-11-11/401, HYD FILTERS B SYS PRESS MODULE REF AMM 29-11-71/401, RETURN FILTER REF AMM 29-11-61/401 AND EDP CASE DRAIN FILTER REF AMM 29-11-51/401. NO METAL WAS FOUND IN OLD FILTERS. #2 ENG DRIVEN PUMP TESTED GOOD AND NO LEAKS FOUND ON #2 DEP OR ON THE 3 HYD SYSTEM FILTERS CHANGED REF AMM 29-11-11-40-801-001.