General Motors moves to fill a vacancy atop its Brazilian arm, naming Grace D. Lieblein that operation’s new president and managing director.

Lieblein takes over the GM do Brasil post left vacant by the departure of Denise Johnson in February following a decline in market share for the auto maker over the past year.

Tapped to succeed Lieblein as president and managing director of GM de Mexico is Ernesto Hernandez, 53, who had been vice president-vehicle sales, service and marketing for that operation. Hernandez reports to GM North America President Mark Reuss.

Lieblein, 50, has held her current position in charge of GM Mexico since December 2008. She reports to GM South America President Jaime Ardila in her new role.