Drum Brakes
Drum Brakes 28.5.1. Brake Layouts There are two types of drum brakes, such as externally contracting and internally expanding. External contracting brakes are preferred for automatic gearboxes. The internal expanding type, along with a drum, is commonly used in braking systems of vehicles. The drum brakes, used with light vehicles, are hydraulically operated. These brakes are commonly used for the rear wheels to complement a disc system at the front. This disc/drum layout permits the front wheels to undertake more braking effort. In addition, the compatibility of a mechanical hand-brake with a drum brake makes this type an obvious option for rear brakes. Various shoe arrangements in use include : • Leading and trailing shoe (L&T) • Two leading shoe (2LS) • Duo-servo. 28.5.2. Leading and Trailing Shoe (L&T) The layout of a leading and trailing shoe brake is presented in Fig. 28.14. This arrangement uses a pair of shoes pivoted at a common anchor point. The free ends of both sh