Nearly 9,000 Freightliner Cascadia and Western Star 4900 trucks are being recalled because the seat could unexpectedly buckle.

The 8,747 Model year 2012 trucks were manufactured from Dec. 22, 2011, through Feb. 23, 2012. These vehicles may be equipped with certain National Seat brand driver's seat. The bases on these seats may have out-of-specification welds that may allow the seat to buckle unexpectedly.

The sudden unexpected movement of the seat could affect a driver's control of the vehicle.

Daimler Trucks North America is notifying owners. Affected trucks will have replacement components installed by DTNA-authorized facilities free of charge.