DETROIT — Ford Motor Co. has expanded a recall of its Windstar minivans over concerns that their rear axles can corrode and break.

The automaker has added 37,000 vans to the recall, bringing the total number of Windstars covered to 612,000 in the U.S. and Canada.

The original recall, announced in August, included vans sold in the 1998 to 2003 model years in 21 U.S. states and Canada where heavy road salt can cause the axles to rust. The corrosion can lead to cracks that can cause the axles to break.

The recall expansion includes 2003 model year vans with heat-treated axles. It also includes vans registered in Utah, where road salt is used in some areas.

Ford had been checking state motor vehicle registration databases to find Windstar owners in the affected states.

It began notifying owners of the additional 37,000 vans about the recall on Dec. 6.

The company said Windstar owners with questions should contact their local dealers or call Ford at 1-866-436-7332.