How Drum Brakes Work

By: Karim Nice

The Emergency Brake

­ The e­mergency brake on a car has to be actuated by a different power source than the primary braking system. The drum brake design allows for a simple cable actuation mechanism. Click here to see an emergency brake in action.

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Figure 8. Emergency brake in operation

When the emergency brake is actuated, a cable pulls on the lever, which forces the two shoes apart.