Ford is joining scores of other companies returning to South Africa now that apartheid has been vanquished. Ford agrees to acquire 45% equity in South African Motor Corp. Ltd. (Samcor) for an estimated $45 million. Ford owned 42% of Samcor through 1988, before it divested all of its South African holdings. The company currently assembles Ford, Mazda and Mitsubishi vehicles. Ford Motor Credit Co. also is re-entering South Africa and is progressing toward a joint-venture agreement with local companies, led by