History Drum brake

several schemes of operation of drum brake, in black highlighted distribution force during braking phase.

the modern automobile drum brake first used in car made maybach in 1900, although principle later patented in 1902 louis renault. used woven asbestos lining drum brake lining, no alternative dissipated heat asbestos lining, though maybach had used less sophisticated drum brake. in first drum brakes, levers , rods or cables operated shoes mechanically. mid-1930s, oil pressure in small wheel cylinder , pistons (as in picture) operated brakes, though vehicles continued purely mechanical systems decades. designs have 2 wheel cylinders.

as shoes in drum brakes wear, brakes required regular manual adjustment until introduction of self-adjusting drum brakes in 1950s. drums prone brake fading repeated use.

in 1953, jaguar fielded 3 cars equipped disc brakes @ le mans, won, in large part due superior braking on drum-equipped rivals. spelled beginning of crossover of drum brakes disc brakes in passenger cars. 1960s 1980s, disc brakes gradually replaced drum brakes on front wheels of cars. practically cars use disc brakes on front wheels, , many use disc brakes on 4 wheels.

in united states, jeep cj-5 (manufactured general) final automobile (produced united states postal service) use front drum brakes when phased out in 1984. however, drum brakes still used handbrakes, has proven difficult design disc brake suitable holding parked car. moreover, easy fit drum handbrake inside disc brake 1 unit serves both service brake , handbrake.

early brake shoes contained asbestos. when working on brake systems of older cars, care must taken not inhale dust present in brake assembly. united states federal government began regulate asbestos production, , brake manufacturers had switch non-asbestos linings. owners complained of poor braking replacements; however, technology advanced compensate. majority of daily-driven older vehicles have been fitted asbestos-free linings. many other countries limit use of asbestos in brakes.