What was found
HYD O'PRESS A CAS MESSAGE WHILE DESCENDING TO DESTINATION. TEMPS ALL NORMAL, PRESSURE BLANKED OFF AND ON THEN OFF FOR REMAINDER OF FLT. NO PRESSURE READING UNTIL SHUTDOWN. WITH ENGINES OFF PRESSURE IS FLUCTUATING 0 TO 500 &CAS MESSAGE RETURNS. REMOVED AND REPLACED LH SYSTEM A HYDRAULIC MANIFOLD ADDITIONAL TIME DUE TO HAVING AN EXTREMELY DIFFICULT TIME ALIGNING ALL THE LINES GOING TO THE MANIFOLD. ALL THE LINES INSTALLED. SERVICED & BLED BOTH SYS MULTIPLE TIMES, PERFORMED MULTIPLE ENG RUNS. PERFORMED OPS & LEAK CHECKED GOOD. NO FURTHER DEFECTS . WORKED IAW MM 29-10-35.