Model-year 2011 and 2012 Thomas Built Saf-T-Liner C2, HDX and MVP-EF school buses are among nearly 9,000 vehicles subject to a recall notice filed earlier this month by Daimler Trucks North America.
The Thomas buses were manufactured from Sept. 1 through Dec. 10, 2010 and are equipped with Cummins ISX or ISL diesel engines. V-Band clamp assemblies (part numbers Q187684, Q187685 and Q187686) that connect the inlet and outlet cone sections to diesel oxidation catalysts or particulate filters include a T-bolt that can fracture and fail under certain stresses or loads.
Daimler said in the NHTSA recall dated Sept. 20 that the fracture or failure of the T-bolt may cause the clamp to loosen and the inlet or outlet sections to disconnect from the DOC or DPF housing. This can allow hot exhaust to vent prior to exiting the tailpipe, which can lead to a fire. If both clamps fail, Daimler added, the DOC or DPF can detach completely.
Daimler and Cummins are identifying owners of the affected buses, and authorized Cummins dealers will perform repairs free of charge. The safety recall campaign began in August.