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Investigation of Truck Brake Failure
A medium duty truck was turning into a construction zone along
a curve from one highway to another . Suddenly, the left front brake locked causing a sharp left turn.
The truck impacted with concrete construction barriers. Six weeks prior, the truck had a complete brake overhaul. Visual and microscopic examination of the left front brake shoes and other debris contained within the truck wheel and brake drum revealed a loose and highly deformed castellated nut and washer. The brake shoes were visibly damaged and the castellated nut exhibited imbedded brake lining material.
This failure and accident resulted from improper
installation of the castellated nut during brake
shoe replacement and brake overhaul.
Photograph A: Brake shoe from left front wheel
of subject truck. Note
gouged and eroded
surface of new brake shoe.
Photograph B: Deformed castellated nut from
brake shoe assembly showing
embedded
brake lining material.
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Truck Accidents
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Dr.
R. Craig Jerner, Ph.D., PE specializes in accident
investigation and metallurgical failure analysis,
with over 30 years experience as a metallurgical
consultant and accident investigator. He has
testified as a metallurgical expert in over 250
depositions and more than 70 court appearances. If you or someone you know should need the services of Dr. Jerner and J.E.I. Metallurgical, please visit our web site at the buttons below, or e-mail Dr. Jerner --- 