Ford Motor Co. (NYSE: F) announced its second recall of Windstar vans for axle problems in two days Thursday, bringing the number of Windstars recalled so far this month to 36,000, the National Highway Traffic Safety Administration reported.

The latest recall affects 9,000 1998 to 2003 model year Ford Windstar vans registered in Puerto Rico. On Wednesday, 27,000 Windstars were recalled in Virginia for similar axle problems.

The Windstar vans in Puerto Rico are being recalled because of an increased risk of the rear axle breaking due to what Ford refers to as high cycles of torsional loading. Essentially, Windstar vans are being recalled in Puerto Rico because the rear axles can break under repeated heavy loads. A cracked axle can cause a loss of vehicle control and an increased risk of crash, according to the NHTSA report.

Windstar axle problems first came to light in 2010 and have been identified in multiple states. Ford will notify owners and dealers and will either install a reinforcement bracket on the rear axle or replace the axles on affected Windstar vans, free of charge. The recall is expected to begin on or about May 21.

For further information, contact Ford at 1-866-436-7332 or call the NHTSA vehicle safety hotline at 1-888-327-4236 or visit the Safercar website. The safety recall campaign number is 12S30.

Ford Motor Company (NYSE: F) shares were up 2 cents to $10.71 late Thursday afternoon.