New Ford vehicles are seen at a parking lot of the Ford factory in Sao Bernardo do Campo February 12, 2015. Grappling with tumbling auto sales and weak economic growth, Brazil wants to derail a pact that would allow unlimited imports of cars from Mexico, sources familiar with the situation say, in a move that could stoke trade tensions between Latin America's largest economies. A treaty between the two nations and auto manufacturers, which sets quotas on how many light vehicles Mexico and Brazil can sell each other, expires in March. Auto trade between the two was then supposed to be fully liberalized. To match Exclusive MEXICO-BRAZIL/AUTOS REUTERS/Paulo Whitaker (BRAZIL - Tags: POLITICS BUSINESS TRANSPORT TPX IMAGES OF THE DAY)