SPECIAL REPORT: NHTSA Office of Defects Investigation alerts truckers to Monon cracking concerns

| 7/10/2003

The National Highway Traffic Safety Administration has asked OOIDA to alert members regarding a safety concern with trailers manufactured by a defunct trailer builder.

NHTSA’s Office of Defects Investigation (ODI) has found that certain 1991-92 Monon trailers may be prone to cracking in the upper coupler plate.

Normal vehicle inspections are unlikely to detect this particular crack condition during the initiation or early stage phases of the cracking. A section of the trailer flooring must be removed to effectively detect cracks originating near the omitted weld in the trailer ribs in the early stages.

Removing a section of the trailer flooring components is not practical for normal inspections, says Kathleen DeMeter, director of ODI, so affected vehicle operators are not likely to be aware of a crack condition until the crack has propagated to the outside of the trailer flooring (on the upper coupler plate) where the crack can be detected by visual inspection.

DeMeter said the advisory applies only to Monon dry freight van trailers, not to the Monon intermodal chassis units designed to carry containers.

One of the problems faced by investigators is that the manufacturer, Monon, filed for bankruptcy in 1997, is dissolved and is no longer in business. In the absence of any responsibility to fix the trailers by the manufacturer, it’s up to the owners to fix them, and NHTSA’s notification makes it clear that the concerns should not be ignored.

ODI recommends that owners of affected vehicles get professional engineering advice regarding appropriate repair methods. Any questions should be directed to Tom Bowman at ODI, (202) 366-6961.