Complex sentence: At first it manufactured brake systems for cars and trucks, supplying General Motors and other automobile manufacturers with hydraulic brake systems and a vacuum booster "TreadleVac" for its production lines for decades.
Split into simpler sentences: At first it manufactured brake systems for cars and trucks, supplying General Motors and other automobile manufacturers. Bendix manufactured both hydraulic brake systems and a vacuum booster "TreadleVac" for its production lines for decades.