Brake cam. Actuating mechanism for the drum brake pads.

The drum brakes are actuated mechanically. The parts involved are the brake lever, or the brake pedal, brake cable, lever, shaft and brake cam. The brake cam sits between the brake pads and forces these towards the drum when braking.

• Replacement for worn components

• Optimum brake performance

• Optimum modulation of the brake

When actuated the metal of the cam rubs on the metal of the brake pads. As a result the cam tends to wear over time. Copper or high temp grease makes the cam last longer, but even if the brake was always meticulously maintained there will be some wear after years and years of use. Once there is an edge worn into the cam this will not only affect braking power but also modulation. Ideally you should be able to finely adjust, or modulate, braking power with the lever or pedal. If, for instance, the rear wheel locks up you should be able to reduce pressure on the pedal slightly and in a controlled way to unlock it. With a worn cam it is possible that even though you reduce the force on the pedal the wheel stays locked because the cam is stuck and cannot be pushed back by the brake shoe return springs. It only unlocks when almost entirely releasing the pedal. With brakes in particular everyone should be aware that all components should be in the best possible condition, not matter what. Hence SIP recommends you check your brake with all its components regularly and replace things that are in less than perfect condition.