There is a Mazda Drum Brake Wheel Cylinder in each drum brake assembly on your vehicle. It is centrally located near the top of the backing plate on which the brake shoes are mounted too on your Mazda.
The drum brake wheel cylinder has to opposing piston in it that are forced out when hydraulic fluid is pushed into the cylinder. Each of these pistons has polymer seal covering the end holding in the hydraulic fluid during the braking action of the brake assembly. Once this polymer seal of the drum brake wheel cylinders dries out and cracks, the hydraulic fluid it is containing will leak out covering the inside of the drum brake assembly impairing its ability to create friction so your Mazda can be stopped.
The driver of the Mazda will know there is a problem since the brake pedal will go farther towards the floor and the braking process will seem less effective. There will also be a puddle of brake fluid on the tire and on the pavement where the leaking drum brake wheel cylinder is located. Each time the brakes are used their effectiveness is decreased since air is replacing the escaping brake fluid.
The Mazda drum brake wheel cylinder should be removed after the drum brake shoes are taken off. Since the shoes are generally saturated with brake fluid, they should also be replaced. Before the mounting bolts of the drum brake wheel cylinder are loosened, the brake line should be taken off. If the mounting bolts are taken off first before the line, when the brake line is removed it could easily become twisted increasing the repair time and cost of this procedure.