What was found
AT FL 370 CRUISE PWR NR 4 OIL PSI DECREASE TO APPROX 20 PSI NR 4 OIL TEMP 150 DEGREE NR 4 OIL QTY NORMAL. PRECAUTIONARY SHUT DOWN NR 4 (0213Z). REMOVED AND REPLACED OIL PROBES XMITTER IAW CH 79-32-1. REMOVED AND REPLACED OIL TEMP SENOR IAW CH 79-54-1. MOTORED ENGINE IAW EWA RUN-UP HANDBOOK. NO LEAKS NOTED, OIL QTY NORMAL. RAN ENGINE TO MAX POWER IAW EWA RAN-UP HANDBOOK. NR 4 OIL SYSTEM OPS CHECKS NORMAL. OIL SYSTEM INSPECTED IAW CH 79-00, MAINT PRECAUTIOUS OIL ALTERS AND DRIP DETECTOR PULLED IAW CH 79-20-5. NO DEFECTED NOTED. OIL DRAINED FROM SYSTEM IAW CH 14-40-1 AND INTERNAL CK OF OIL TANK PERFORMED. FOUND BRACKET ON SUCTION LINE BROKEN. REMOVED AND REPLACED OIL TANK IAW CH 79-70-1.