1. It develops pressure, causing the wheel cylinder pistons to move lowest the rotors (disc) or drums.
2. After all the shoes or push rods produce sufficient friction, the master cylinder helps to equalize the pressure required for braking.
3. It keeps the system full of fluid as the brake beings wear.
4. It can maintain a slight pressure to keep continents (air and water) from entering the system. Master Cylinder Components In its simplest from, a master cylinder consists of housing reservoir, piston, rubber cups return spring and rubber boots etc.
A cylinder is machined in the housing of the master cylinder, the spring, cup and metal piston slide in this cylinder. Two parts are drilled between the reservoir and the cylinder. The cup and piston in the master cylinder arc used to pressurize the brake system. When they are pushed forward, they trap the fluid, building pressure.
The master cylinder intake port, or vent allows fluid to enter the rear of the cylinder as the piston slides forward. Fluid flows out of the reservoir, through the intake port and in to the area behind the piston and cup.
When the brake pedal is released, the spring forces the piston and cup hack in the cylinder. If needed the rubber cup moves forward allowing fluid to enter the area in front of the piston and cup. Usually small holes are drilled in the edge of the piston so that fluid can how fast in the cup.
The compensating port releases extra pressure when the piston returns to the released position. Fluid can flow back in to the reservoir through the compensating port. The action of the intake port and the compensating port keeps the system full of fluid.