Drum Brake Function
The drum brakes are of the duo-servo type. Servo drum brakes mean that the friction force from the primary shoe is directly transferred to the secondary shoe when applied towards the drum. The combined friction force is absorbed by the armature in the same place that the expander is applied in. Duo-servo means that servo assistance is available at the front and back. Force is transferred between the shoes via an adjustable or fixed link. The expander is applied via a wire, which is controlled either by a hand brake lever or foot brake pedal.
The shoes are held in position in the drum brakes via a securing spring, which is fixed in the protective plate.