Daimler Trucks North America notified NHTSA last week that some Stabilus Bloc-o-lift driver seats were improperly welded into certain Thomas Built Buses models.

The two recalls, NHTSA campaign ID numbers 10V486000 and 10V487000 affect 300 models of Thoams HDX, MVP-EF and Saf-T-Liner C2 school buses. The vehicles have manufacturing dates falling between March 17 and Dec. 7 of last year.

Daimler said the improper weld that holds the seat mounting tab to the shock body can break, which could lead to the driver losing control of the bus and a potential crash. Authorized Thomas dealers will perform repairs free of charge to owners starting on or around Dec. 10 of this year.