MECHANIC REPORTS AN A320 ARRIVED WITH A VEERING TO THE RIGHT PROBLEM. ONLY AFTER REPLACING THE STEERING SERVO CONTROL (6GC) TWICE; DID THEY REALIZE THE VENDOR OVERHAULED STEERING SERVO UNITS THEY INSTALLED WERE ALSO DEFECTIVE.

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WE RECENTLY WORKED ON ACFT X. IT CAME IN ON OCT/XA/08 FOR ACFT VEERING TO R. WE TROUBLESHOT THE R TROUBLESHOOTING MANUAL AND REPLACED STEERING SERVO CONTROL (6GC). ACFT STILL PULLED TO R; AFTER SEVERAL SHIFTS; MANY PARTS AND MANUAL PWR. NOT TO SPEAK OF LOST REVENUE. ON OCT/XC/08 THEY REPLACED SERVO VALVE (6GC) ONCE AGAIN AND SYMPTOM WAS CURED. WHAT ARE WE DOING ABOUT VENDOR OVERHAULED PARTS? THEY ARE PROVIDING AIRLINE WITH A POOR PRODUCT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THEY FOLLOWED THE TROUBLE SHOOTING MANUAL (TSM) AND WERE CORRECT IN LOCATING THE SUSPECTED CAUSE OF THE A320 VEERING TO THE RIGHT. BUT; WHEN THEY REPLACED THE STEERING SERVO CONTROL ON THE AFT SIDE OF THE NOSE GEAR STRUT THE FIRST TIME AND THE AIRCRAFT STILL VEERED TO THE RIGHT; THEY FIGURED THEY HAD MISSED SOMETHING IN THE TSM PROCEDURE AND REPLACED MORE PARTS AND SENSORS. REPORTER STATED WHEN THEY DECIDED TO REPLACE THE STEERING SERVO AGAIN AND THE PROBLEM WAS CORRECTED; HE FELT THE SITUATION ONCE AGAIN SHOWED THE CONTINUING PROBLEM HIS CARRIER IS HAVING WITH OUTSIDE VENDORS OVERHAULING PARTS THAT STILL FAIL WHEN INSTALLED IN THEIR AIRCRAFT. REPORTER STATED THEIR TROUBLE SHOOTING PROCESS WAS CORRECT; BUT THE NEW PART WAS BAD. HE QUESTIONS WHETHER HIS CARRIER'S QUALITY ASSURANCE DEPARTMENT IS DOING ANYTHING TO ADDRESS THIS ISSUE.