NHTSA Investigation EA88024

AXLE NUTS

ANALYSIS:INTERNAL FRUEHAUF MEMORANDUMS SHOW A LONG TERM PROBLEM HASEXISTED WITH THE AXLE NUT FASTENING SYSTEM ON MULTI-AXLE VEHICLES.A HEAVYDUTY NUT WAS MADE AVAILABLE IN LATE 1976 FOR SEVERE USE APPLICATION AND2 YEARS LATER WAS INSTALLED ROUTINELY DURING TRAILER PRODUCTION.PROBLEMSCONTINUED, RESULTING IN THE AVAILABILITY OF A HEAVY DUTY DOUBLE AXLE NUT IN1981, AND ITS ROUTINE INSTALLATION ON SEVERE SERVICE VEHICLES IN 1983.ADDITIONALLY, FRUEHAUF INTERNAL DOCUMENTS INDICATE THAT SOME AXLES AND AXLENUTS HAD AN OUT OF TOLERANCE PROBLEM WHICH INCREASED THE LIKELIHOOD OFTHREADS STRIPPING AND WHEEL SEPARATION.SUMMARY OF INFORMATION FROM MANUFACTURER:A LONG TERM PROBLEM EXISTED WITHVARIOUS CORRECTIVE MEASURES BEING IMPLEMENTED APPARENTLY UNSUCCESSFULLY,UNTIL THE AVAILABILITY OF THE DOUBLE NUT KIT IN 1983.FRUEHAUF'S POSITIONIS THAT AN AXLE NUT PROBLEM DOES NOT EXIST (DUE TO A LACK OF WARRANTYCLAIMS) AND THEREFORE THERE IS NO THREAT TO PUBLIC SAFETY.STATUS:IR BEINGDRAFTED.===

An investigation is a separate record from a recall and from a manufacturer communication. A manufacturer campaign to repair a safety defect or a failure to meet a federal safety standard.