Wescast, which supplies exhaust manifolds and other components for cars and light trucks, said union members at the machining plant began a legal strike on Saturday morning.

"The company has put plans in place to ensure continued supply of parts to customers," it said in a brief statement.

The Canadian Auto Workers union said in an email to Reuters that 75 workers have walked off the job.

The union said in an earlier statement it was meeting with members on Sunday to discuss a plan to escalate actions and was operating a 24-hour picket line.

Wescast says on its website that it has a 51 percent share of the North American exhaust manifold market and even larger share among the Detroit Three: General Motors Co (GM.N), Ford Motor Co (F.N) and Fiat SpA's (FIA.MI) Chrysler Group LLC.

Wescast announced in June it agreed to be bought by China's Sichuan Bohong Industry Co Ltd but the deal has not yet closed.

(Reporting by Jeffrey Hodgson; Editing by Bill Trott)

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