AN AIRCRAFT TIRE SHOP MECHANIC REPORTS ABOUT VIBRATIONS ON AIRBUS A320'S CAUSED BY CONFLICTING BUILDUP PROCEDURES OF THE TIRE WHEEL HALVES. LACK OF PROPER REVISION PAPERWORK IN THE COMPONENT MAINTENANCE MANUAL ALSO A PROBLEM.

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BEFORE THE WKEND; THERE WERE RPTS OF PROB WITH VIBRATION ON AIRBUS THE TIRE SHOP CREW WAS MANDATED TO BUILD THE AIRBUS TIRE ASSEMBLIES WITH THE 'L' SIDE OF THE WHEEL HALVES TO BE 180 DEGS APART. THROUGHOUT THE NEXT SEVERAL DAYS; WE HAVE FOUND SEVERAL NOSEWHEEL HALVES WITH THE MISSING 'L' STAMP ON THE FLANGE OF THE AIRBUS WHEEL HALVES. THE MISSING STAMPS WERE DUE TO NORMAL WEAR AND TEAR FROM HANDLING OF THE WHEELS HALVES THROUGHOUT THE YRS. THESE WHEELS WERE THEN QUARANTINED FOR FURTHER INFO GATHERING. I WAS DIRECTED TO BUILD THESE ASSEMBLIES WITHOUT THE PROPER DOCUMENTATION/CLARIFICATION OF THE MISSING 'L.' I HAVE MADE IT CLEAR TO MY SUPVR THAT THE CURRENT COMPONENT MAINT MANUAL DID NOT HAVE ENOUGH INFO TO COVER THE PROB. UPDATE MANUAL PROC TO REFLECT THE NEW FINDINGS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THAT IN THE PAST; THE PROCEDURES THEY USED IN THEIR COMPONENT MAINTENANCE MANUAL (CMM) TO ACHIEVE THE BEST POSSIBLE BALANCING WHEN THE TWO BF GOODRICH WHEEL HALVES WERE PUT TOGETHER; WAS TO MAKE SURE THE 'L' LETTER STAMPED INTO EACH WHEEL HALF WAS 180 DEGREES FROM EACH OTHER. REPORTER STATED HIS MANAGEMENT TOLD THE MECHANICS TO IGNORE THE CMM DIRECTIONS AND JUST LINE UP THE 'L' LETTER OPPOSITE EACH OTHER INSTEAD OF THE 180 DEGREE SEPARATION. REPORTER STATED WHEN HE REQUESTED DOCUMENTATION AND A REVISION BE MADE TO THEIR CMM GIVING THEM AUTHORIZATION TO DEVIATE FROM THE 180 DEGREE REQUIREMENT; THEY WERE TOLD THE REVISION WAS COMING. IN THE MEANTIME; THERE WAS A BIG SPIKE IN THE NUMBER OF WHEEL VIBRATION ISSUES ON THEIR A320'S. REPORTER STATED THERE ARE TIMES WHEN THE 'S' MARK ON THE WHEEL HALVES HAVE BEEN WORN OFF; MAKING ALIGNMENT WITH THE LETTERS IMPOSSIBLE. IN THOSE SITUATIONS; THEY USE THE WHEEL HALF TIRE GAUGE PORT AS THE LIGHTWEIGHT SIDE OF THE WHEEL HALF FOR ALIGNMENT. REPORTER STATED DYNAMIC BALANCING IS NOT DONE AFTER THE TIRE IS MOUNTED TO THE WHEEL AND BECOMES A COMPLETE ASSEMBLY. THAT IS BECAUSE THE TIRE HAS A RED DOT ON THE SIDEWALL INDICATING THE OPTIMUM BALANCING SPOT FOR THE TIRE. WITH THE WHEEL HALVES PROPERLY ALIGNED TO EACH OTHER AND THEN TO THE RED DOT; BALANCE SHOULD BE CLOSE ENOUGH FOR SERVICE. REPORTER ALSO STATED THEIR ENGINEER BELIEVED SOME OF THE VIBRATION ISSUES WERE NOT RELATED TO THE WHEEL HALVES BALANCING ALIGNMENT ISSUE; BUT WERE ASSOCIATED WITH THE MAIN GEAR DAMPERS THAT HAD NEVER BEEN WORKED ON. THESE DAMPERS ARE CYLINDER SHAPED; AND CONSTRUCTED INTERNALLY SIMILAR TO A WAFFLE BOARDS LINED UP. APPARENTLY SOME HAVE BEEN FOUND BROKEN AND RUSTED OUT INTERNALLY. REVISIONS HAVE BEEN COMPLETED IN THEIR CMM'S.