What was found
AIRCRAFT WAS PULLED INTO HANGAR FOR MAINTENANCE. TECHNICIAN NOTICED OIL RUNNING OUT OF LT ENGINE COWLING. AFTER REMOVING COWLING, FOUND LINE FROM UNFEATHERING PUMP TO NTS/BETA SWITCH CRACKED ALL THE WAY AROUND AT THE FERREL FOR THE 'B' NUT AT THE MANIFOLD. (THIS IS A CESSNA SUPPLIED LINE). INSTALLED NEW LINE, GROUND RAN, LEAK CHECKED OK. SUBMITTER SUGGESTS MANDITORY REPLACMENT AT ENGINE OVERHAUL. LINE IS MADE OF STAINLESS STEEL TUBING.