1. Fluid Reservoirs: The master cylinder has two fluid reservoirs, one for the front brake circuit and one for the rear brake circuit.
2. Compensating Port: The compensating port is a small opening or passage located between the two fluid reservoirs inside the master cylinder.
3. Pressure Equalization: When the brake pedal is depressed, the master cylinder piston moves forward and pressurizes the brake fluid in both the front and rear circuits. As pressure builds up in the front circuit, some of the fluid flows through the compensating port and into the rear circuit.
4. Balanced Pressure: The compensating port allows the pressure to equalize between the front and rear brake circuits. This ensures that the front and rear brakes are actuated with the same force, preventing the rear brakes from locking up before the front brakes.
5. Proportioning Valve: In modern vehicles, the master cylinder compensating port is often combined with a proportioning valve. The proportioning valve further regulates the fluid distribution to the front and rear circuits based on the load on the vehicle, ensuring optimal braking performance in various driving conditions.
By balancing the pressure between the front and rear brakes, the compensating port helps achieve safe and controlled braking, especially in older vehicles with drum brakes where the rear brakes are more prone to locking up.
