Hitting the Brakes: A History of Automotive Brakes
Starting cars with a hand-crank was never easy and bringing them to a halt wasn't a cake walk, either. Many early cars used simple "spoon" brakes like carriages had: a driver relied on a lever system that moved a block of wood against the wheels. These worked relatively well for speeds of 10-20 mph in sparse traffic. By the late 1890s, though, when the Michelin brothers came out with rubber pneumatic tires, the wood block idea was pretty useless because the wood ground the rubber down pretty badly.
In 1898, an enterprising inventor from Cleveland, Elmer Ambrose Sperry, designed an electric car with front-wheel disc brakes, built by the Cleveland Machine Screw Co. With disc brakes, a caliper with brake pads pinches a rotor or disc—like bicycle brakes. The man credited with the invention of the disc brake, however, was English engineer Frederick William Lanchester who patented the idea in 1902. The biggest problem with his brakes, though, because copper brake pad linings moved against a metal disc, was the horrible screeching noise they made. It took another five years for someone else to cure the noise problem: Herbert Frood, a fellow Brit, lined the pads with long-lasting asbestos. In fact, asbestos continued to be used in car brakes until the 1980s when health and safety concerns eliminated it. Still, the disc brake didn't enjoy much popularity. It wasn't until the 50s that European cars began the wide use of disc brakes. In 1967, Federal Motor Vehicle Safety Standard 105 set specific performance tests that led to the widespread introduction of disc brakes on American cars in the early seventies. But we'll leave the disc brakes for now and focus instead on the later-introduced but, initially, more popular drum brakes.
Mechanical Drum Brakes
The first, or among the first, to wrap a cable around a drum anchored to the vehicle's chassis—the basic idea for drum brakes—was Gottlieb Daimler, in 1899. Wilhelm Maybach, designer of the first Mercedes, utilized rudimentary, mechanical drum brakes in 1901. These were steel cables wrapped around the drums of the rear wheels and operated by a hand lever. Louis Renault, however, is the man credited with the 1902 invention of the drum brake which would become standard for automobiles. In drum brakes, brake shoes generate friction by rubbing against the inner surface of a brake drum attached to a wheel. There are external-contracting brakes in which the brake band surrounds the drum and internal-expanding drum brakes in which the shoes, supported by a back plate, are forced outward against the drum.
In the U.S., one of the first to manufacture drum brakes was the A. H. Raymond Co. of Bridgeport, Connecticut, opened in 1902 as a four-man shop that built brakes, brake linings, and clutch facings. Re-named Royal Equipment Co. by 1904, the company continued to improve brakes, particularly with an asbestos and copper-wire brake lining known as "Raybestos". The claims the Raymond Co. could make were that it had "double acting" brakes—stopping both forward and backward motion and that the driver could now choose to stop suddenly or gradually.
In 1902, Ransom E. Olds of Oldsmobile tested an early external-contracting brake design during a race on Riverside Drive in New York City. The design called for wrapping a flexible stainless steel band around the rear axle drum. The driver depressed the foot pedal mounted on the floor to operate the brake band which gripped the drum. Olds was pitting his car's braking power against that of a tire brake (a pad applied to the tire by means of a long lever) for a four-horse coach and an internal drum, expanding-shoe design for a Victoria horseless carriage. Stopping from a speed of 14 mph, the horse-drawn carriage (which may not really have gone as fast as the cars) stopped in 77.5 feet, the Victoria in 37 feet, and the Olds in 21.5 feet. The results were impressive enough that by 1903 many manufacturers were using the Olds brake design and by 1904 virtually all manufacturers had gone to the external brake on each rear wheel.
There were some notable drawbacks with external brakes, though. At times, while on hills, the brake could come unwrapped and give way, sending the car rolling backward. Drivers could remedy that problem by getting a passenger to jump out and wedge a wooden chock beneath the rear wheel. Also, because the brakes were exposed to the elements, they didn't last long and required frequent replacement. Brakes slipped in wet weather and daily dirt and grime wore them away. Consider how you might like having to have your brakes replaced every couple of hundred miles. It didn't take long for manufacturers to return to internal-expanding drum brakes. Internal brake shoes, under pressure, stayed against the drums, preventing cars atop hills from rolling backward. And because the parts were internal, brakes could last 1,000 miles or more.
As speeds—and traffic—increased, manufacturers began to look for improvements. One arose in 1915 with the Duesenberg entered in the Elgin Road Race (sponsored by the Elgin Watch Company). With the innovation of applying internal brakes to both front and rear wheels, its driver could reach 80 mph on the straightaway, then brake to a much slower speed to go round the tight curves. In 1919, the French-made Hispano-Suiza H6B utilized a single foot pedal to operate the coupled four-wheel brakes, a departure from the common requirement that a driver had to apply a separate hand and foot brake simultaneously. At the 1924 New York Auto Show, only Duesenberg and Rickenbacker offered four-wheel brakes. In late 1923, Chalmers offered them as an option priced at $75—and Buick, Cadillac, Chrysler, and others fell in line with four-wheel brakes soon thereafter. While competitors that did not offer them made the claim that these brakes were unsafe, they were definitely here to stay. By the 1980s, most cars came with four-wheel drive disc brakes.
Another improvement came about in 1918 when Malcolm Lougheed (later changing his name to Lockheed, of aviation fame) invented a hydraulic braking system. Mechanical brakes, besides requiring drivers to exert significant force on the brake pedal, did not brake all wheels evenly, sometimes leading to loss of control. Using cylinders and tubes, Lockheed sent fluid pressure against brake shoes, pushing them against the drums. It required much less exertion for the driver to apply these brakes. The hydraulic system was a definite improvement and the avant garde 1921 Model A Duesenberg was the first production car to use four-wheel hydraulic brakes. It was followed by Chalmers cars in late 1923. Walter Chrysler had been brought aboard at Chalmers to improve its financial picture—but the company foundered shortly thereafter nonetheless. In 1924, he was leading Chrysler in its first year and using four-wheel hydraulic brakes that were based on the Lockheed principle but completely redesigned. The original Lockheed brakes leaked badly, in large part because of the use of rawhide cup seals to contain the hydraulic fluid. Because the rawhide dried up and shrank over time, Chrysler replaced them with rubber cup seals. Lockheed appreciated the improvement and OK'd Chrysler to use his design royalty-free—so long as he could also add the improvement to the original patented Lockheed design. The new brake type, known as Chrysler-Lockheed hydraulic brakes, were ones Chrysler utilized from 1924 to 1962.