Editing Drum brake (section)

==History==
[[File:Tipologia tamburo.svg|thumb|Several schemes of drum brake operation; the distribution force during the braking phase is highlighted in black.]]
The modern [[automobile]] drum brake was first used in a car made by [[Wilhelm Maybach|Maybach]] in 1900, although the principle was only later patented in 1902 by [[Louis Renault (industrialist)|Louis Renault]]. He used woven asbestos lining for the drum brake lining, as no alternative material dissipated heat more effectively, though [[Maybach]] had used a less sophisticated drum brake. In the first drum brakes, levers and rods or cables operated the shoes mechanically. From the mid-1930s, oil pressure in a small [[wheel cylinder]] and [[piston]]s (as in the picture) operated the brakes, though some vehicles continued with purely mechanical systems for decades. Some designs have two wheel cylinders.

As the shoes in drum brakes wear, brakes required regular manual adjustment until the introduction of self-adjusting drum brakes in the 1950s. Drum brakes are also prone to [[brake fade]] with repeated use.<ref>{{cite web |url=http://www.crashforensics.com/brakefailure.cfm |title=Brake Failure Analysis |access-date=2015-05-19 |url-status=dead |archive-url=https://web.archive.org/web/20150409074407/http://www.crashforensics.com/brakefailure.cfm |archive-date=2015-04-09 }}</ref>

[[Jaguar Cars]] fielded three cars equipped with [[disc brake]]s at [[1953 24 Hours of Le Mans|Le Mans]] in 1953, where they won, in large part due to their superior braking over drum-equipped rivals.<ref>{{Cite web |url=http://www.motorsportmagazine.com/race/sports-cars/le-mans/le-mans-1953-jaguars-gigantic-leap/ |title=Le Mans 1953: Jaguar's gigantic leap - History, le Mans - Motor Sport Magazine |access-date=2015-05-19 |archive-date=2015-09-05 |archive-url=https://web.archive.org/web/20150905102834/http://www.motorsportmagazine.com/race/sports-cars/le-mans/le-mans-1953-jaguars-gigantic-leap/ |url-status=dead }}</ref> This spelled the beginning of the end for drum brakes in passenger cars. From the 1960s to the 1980s, disc brakes gradually replaced drum brakes on the front wheels of cars (which receive the majority of braking force). Now practically all cars use disc brakes on the front wheels, and many use disc brakes on all four wheels.

In the United States, the [[Jeep CJ-5]] (manufactured by [[AM General]]) was the final automobile (produced for the United States Postal Service) to use front drum brakes when it was phased out in 1986. However, drum brakes are still often used on the rear wheels, and for [[parking brake]]s. Some vehicles utilize a "drum-in-hat" parking brake, where the brake shoes are arranged inside the center portion (hat) of a disc brake rotor, which acts as the drum.<ref>{{Cite web|title=Drum-In-Hat Parking Brake Kits|url=https://www.carlsonqualitybrakeparts.com/wp-content/uploads/2018/12/Carlson-Drum-In-Hat-Parking-Brake-Kits-Flyer-2018.pdf|access-date=2020-10-17}}</ref>

Early brake shoes contained [[asbestos]]. When working on brake systems of older cars, care must be taken not to inhale any dust present in the brake assembly. After the United States Federal Government began to regulate asbestos production, brake manufacturers had to switch to non-asbestos linings. Owners initially complained of poor braking with the replacements, but brake technology eventually advanced to compensate. A majority of daily-driven older vehicles have been fitted with asbestos-free linings. Many other countries have also prohibited the use of asbestos in brakes.