ANN ARBOR, Mich. Jack Weidenbach, former University of Michigan Athletic Director (1990-94), has passed away at the age of 99. Weidenbach's association with Michigan spanned nearly three decades. He joined U-M in 1966 and held several major management positions on campus. Before moving to the athletic department, he was director of business operations and managed the university's physical plant, purchasing, public safety, occupational safety, and environmental health.