Investigations
WHEEL STUD FRACTURE
NHTSA Engineering Analysis EA03004 - closed, opened 2003-04-10.
NHTSA investigation EA03004 is a Engineering Analysis opened on 2003-04-10 and currently closed. The subject is tracked inside the Office of Defects Investigation queue. Latest activity on this investigation was logged on 2004-08-30 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
An Engineering Analysis like EA03004 is the deeper technical phase that follows a PE. NHTSA requests design, warranty, and field-failure data from the manufacturer, conducts its own testing when needed, and determines whether the evidence supports a safety defect finding that would compel a recall.
Investigators summarized the matter as follows: "THE SUBJECT VEHICLES RANGE IN AGE FROM 4¿7 YEARS IN SERVICE, WITH AVERAGE MILEAGES ESTIMATED TO RANGE FROM 50 TO 100 THOUSAND MILES. AT THESE MILEAGES, THE SUBJECT WHEELS ARE LIKELY TO HAVE BEEN REMOVED AND REINSTALLED M..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time.
Investigation Summary
THE SUBJECT VEHICLES RANGE IN AGE FROM 4¿7 YEARS IN SERVICE, WITH AVERAGE MILEAGES ESTIMATED TO RANGE FROM 50 TO 100 THOUSAND MILES. AT THESE MILEAGES, THE SUBJECT WHEELS ARE LIKELY TO HAVE BEEN REMOVED AND REINSTALLED MULTIPLE TIMES FOR VARIOUS SERVICE PROCEDURES. ODI IS CONCERNED ABOUT THE HIGH WHEEL SEPARATION RATES IN THE MY 1997-98 WINDSTAR VEHICLES EQUIPPED WITH ALUMINUM ALLOY WHEELS. HOWEVER, ANALYSIS OF FAILURE DATA INDICATES THAT MOST OF THE INCIDENTS IN THAT POPULATION OF VEHICLES OCCUR AFTER THE VEHICLES HAD ACCUMULATED 30 THOUSAND MILES OF SERVICE. THE FACTORS THAT INCREASE THE RISK THAT INADEQUATE CLAMP LOADS MAY BE ACHIEVED DURING SERVICE-RELATED WHEEL INSTALLATION ARE NOT UNIQUE TO THE SUBJECT VEHICLES. TESTING CONDUCTED BY FORD AND VRTC INDICATE THAT THE MY 1998 WINDSTAR ALUMINUM WHEEL FASTENING SYSTEM PERFORMS SIMILAR TO THE WHEEL FASTENING SYSTEMS ON PEER MINIVANS. NO DESIGN OR MANUFACTURING DEFECTS WERE IDENTIFIED IN THE WHEEL FASTENING SYSTEMS OF THE SUBJECT VEHICLES. FORD WILL SEND A MAILING TO OWNERS OF WINDSTAR VEHICLES WITH ALUMINUM WHEELS THAT HAVE HIGH WHEEL SEPARATION RATES THAT REVIEWS THE APPROPRIATE WHEEL FASTENING PROCEDURES AND STATES THAT THE WHEEL NUTS SHOULD BE TIGHTENED TO THE NOMINAL TORQUE, 100 FT-LBS (136 NM), AND RE-TIGHTENED TO THE SAME TORQUE AFTER 500 MILES. FORD¿S LETTER ALSO STATES THAT IT IS ¿A GOOD PRACTICE TO BE SURE THAT BEFORE INSTALLING THE WHEEL THE ALUMINUM WHEEL MOUNTING SURFACE, WHEEL LUG NUT AREA, AND THE MOUNTING FLANGE ARE FREE FROM DIRT, DEBRIS, AND LOOSE RUST TO ENSURE THE WHEEL IS SEATED CORRECTLY AND THE WHEEL LUG NUTS REMAIN FULLY TIGHTENED.¿ ODI WILL CONTINUE TO MONITOR THE INCIDENCE OF WHEEL FASTENER FAILURES IN THE SUBJECT VEHICLE POPULATION. ACCORDINGLY, THIS INVESTIGATION IS CLOSED. THE CLOSING OF THIS INVESTIGATION DOES NOT CONSTITUTE A FINDING BY NHTSA THAT A SAFETY-RELATED DEFECT DOES NOT EXIST. THE AGENCY WILL TAKE FURTHER ACTION IF WARRANTED BY THE CIRCUMSTANCES. FOR ADDITIONAL INFORMATION, SEE
About This Investigation Type
An Engineering Analysis (EA) is the in-depth phase following a Preliminary Evaluation. NHTSA engineers conduct testing, collect data from manufacturers, and perform detailed technical analysis to determine whether a safety defect exists. An EA may lead to a voluntary recall by the manufacturer or, in rare cases, a mandatory recall order.
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. about how PlainCars sources NHTSA data.
Read our methodology - how this data is sourced, computed, and verified.