AN EMB-135 ACFT HAD THE LEFT ENGINE FWD UPPER MOUNT YOKE AFT BUSHING MANUFACTURED AND REPLACED. REQUIRED HEAT TREATMENT OF BUSHING WAS NOT ACCOMPLISHED.

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I WAS ASKED TO MANUFACTURE BUSHING FOR ACFT L-HAND ENG FORWARD YOKE IN ACCORDANCE WITH SRM. ON THE BOTTOM OF PAGE X IT CALLS OUT FOR MATERIAL CORROSION RESISTANT STEEL 15-5PH; PRECIP HARDENED; AND PASSIVATED. I KNOW WE HAVE CERTIFIED 15-5PH STEEL BUT I WAS NOT SURE ABOUT PRECIP HARDENED OR PASSIVATED. I WENT TO OUR ENGINEERING DEPT AND QUESTIONED THAT. I WAS TOLD BY MR X THAT PRECIP HARDNESS WAS ALREADY DONE TO 15-5PH STEEL; AND HE WOULD WRITE EMBRAER FOR PERMISSION TO SKIP THE PASSIVATION PROCESS. WHEN I RECEIVED THE PAPERWORK FOR OMISSION OF THE PASSIVATION I FELT I COULD GO AHEAD AND MANUFACTURE BUSHING. I MANUFACTURED BUSHING AND DELIVERED IT TO MECHS ALONG WITH CERTS AND FAX FROM EMBRAER. I WAS ASKED TO PERFORM THIS TASK AGAIN; AND I REQUESTED MORE INFO. I REVIEWED CURRENT INFO AND NOTIFIED INSPECTION DEPT I DID NOT FEEL I WAS IN COMPLIANCE ON AN ACFT THAT I DID LAST. THEY HELPED ME DETERMINE THE ACFT. REQUESTED AND RECEIVED A 5000 HR DEFERRAL FROM THE MANUFACTURER. AN ENGINEERING ORDER WAS WRITTEN TO DEFER THE REPLACEMENT OF THE BUSHING FOR 5000 HRS. SUPPLEMENTAL INFO FROM ACN 732725: I INSTALLED A LOCALLY MANUFACTURED BUSHING THAT OUR MACHINE SHOP MADE. I INSTALLED IT; SIGNED IF OFF; QA SIGNED IT OFF. THE MACHINIST THAT MADE THE BUSHING INFORMED ME THAT HE JUST REALIZED THAT HE DID NOT HEAT TREAT IT. THE SRM DOES NOT CLARIFY HEAT TREATMENT AS A STEP.