Drum brakes operate in a hydraulic system of cylinders with curved brake pads to stop the motion of the wheels of a vehicle. You can find cheap replacement drum brakes by searching with a registration number here.
Braking systems in standard vehicles can function by either disc brakes or drum brakes. The latter are reliant on brake pads that push up against the inner surface of a brake drum to stop a vehicle. The friction caused by this motion every time the brakes are pressed means that the materials inside drum brake systems can wear down over time. Liquids and lubricants are used to prevent the process of corrosion, but brake drums can fail mechanically, too. If brakes become soft to the touch on the pedal, you must get them checked immediately. Vehicles with faulty brakes are incredibly dangerous. Replacement brake drums are specific to certain cars and vans, so be sure to search with your make and model to find the right one for your vehicle and consult a mechanic to fit it for you.