The Hispano-Suiza H6, a 1919 luxury car, featured a drum brake system so advanced that it incorporated a servo mechanism powered by the engine’s exhaust gases, allowing lighter pedal pressure to achieve stopping power comparable to much heavier vehicles—yet this ingenious design was so ahead of its time that competing manufacturers didn’t fully understand how it worked, and the technology essentially vanished when hydraulic brakes became standardized in the 1930s, making it one of automotive history’s most forgotten innovations.
Car Fact #31 — July 17, 2026
