What was found
RT BLEED AIR ISOLATION VALVE FAULT ON OVHD PANEL. TRANSFERRED TO MDDR 137572, IAW MEL 36-11-06. FOUND RT ISOLATION VALVE LIGHT STAYING ON WHEN SWITCH IS IN OPEN POSITION. OPERATIONS CHECKS NORMAL IN CLOSED POSITION. REMOVED AND REPLACED K18 RELAY VALVE OPEN RELAY, PER SWPM 20-81-18, NO HELP. SLAVED IN RT ISOLATION VALVE ON LEFT SYSTEM, PROBLEM FOLLOWED. REMOVED AND REPLACED RT ISOLATION VALVE, PER AMM 36-11-04. PRESSURIZED PNEUMATICS, PER AMM 36-00-00 AND RAN RT ENGINE, PER AMM 71-00-00. OPERATIONS AND LEAK CHECK GOOD. THIS CLEARS MDDR 137572, PLACARD REMOVED, MCC NOTIFIED.