A B757-200 RPTED L ENG HIGH VIBRATION AFTER A FAN BLADE LUBRICATION REPAIR CAUSED BY THE BAL WT RING POSITIONED INCORRECTLY.

Narrative

L ENG VIBRATION TREND SPIKE 2 MIL AND ABOVE. FAN LUBE WAS REQUESTED BY PWR PLANT ENGINEERING. LUBE WAS ACCOMPLISHED PER MAINT MANUAL 72-31-13. THE MECHS THAT ACCOMPLISHED THE TASK MARKED THE PARTS AT REMOVAL. AS LEAD MECH; I WAS NOT PRESENT FOR THE ENTIRE JOB. I DID SEE PARTS WITH MARKS AND BLADES NUMBERED. AFTER REASSEMBLY; I WAS PRESENT FOR THE VIBRATION SURVEY RUN. IT WAS ACCOMPLISHED PER MAINT MANUAL 71-00-00 TEST 6. THE PEAK VIBRATION NOTED WAS 2.1 AT TKOF PWR. THE LIMIT IS 2.5 SPIKES ABOVE 2 MIL HAD BEEN RECORDED IN THE TREND DATA. THE OTHER MECH AND I FELT THE RUN WAS SATISFACTORY BASED ON THE MAINT MANUAL LIMITS AND TREND DATA THE ACFT WAS RELEASED FOR SVC. INFLT; THE L ENG VIBRATION REACHED A PEAK OF 3.4 MIL. AFTER TALKING TO ENGINEERING AND THE MECH THAT ACCOMPLISHED THE LUBE; WE TOLD ENGINEERING THE FIRST PLACE WE RECOMMENDED TO LOOK WOULD BE THE BAL WT RING. THIS WAS RECOMMENDED DUE TO AFTER HANDLING OF PARTS THE MARKINGS WERE NOT AS CLRLY DEFINED. THE CORRECTIVE ACTION WAS TO RECLOCK THE WT RING. NO ENG DAMAGE WAS NOTED AND ACFT CONTINUED IN SVC WITH NO FURTHER VIBRATION PROB THAT WE ARE AWARE OF.