Drum Brakes

 This is part of my Brief Guide To Brakes series – a result of my research for Edinsolar, the University of Edinburgh’s solar vehicle team.



• drum shoes pushed into the sides of the drum cylinder
• friction slows down the drum cylinder
• return springs pull drum shoes away from cylinder to release brakes

Often the drum brake contains 3 main parts:

Main Drum Brake

• piston pushes drum shoes


Emergency/Parking Brake

• pull on a lever attached to steel cables
• steel cables pull shoes directly against the drum
o completely mechanical, no dependence on the hydraulics



• as the shoe pads wear away, the piston needs to push the shoes further to reach the drum
• after a certain level of use, the automatic self-adjusters move the rest position of the shoes so they are closer to the drums and have less to travel again


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