A master brake cylinder provides the hydraulic pressure to operate the wheel brake calipers and cylinders. A master cylinder is basically a pump, operated by the brake pedal. It transfers brake fluid into the brake lines. A reservoir on top of the cylinder provides extra brake fluid to compensate for brake pad wear. As brake pads wear, the pistons in the calipers or wheel cylinder extend more and more, drawing ever more fluid in the increasing space behind the pistons.
A braking system should be failsafe, but you can't rule out defects entirely. For that reason, modern braking systems have two separate hydraulic circuits. In case one circuit fails, the other still provides stopping power. As front wheel braking action is much stronger than rear wheel braking action, on most cars each circuit operates one front wheel and the diagonally opposed rear wheel. However, more elaborate systems are also used.
As there is only one brake pedal and one master cylinder, master cylinders are usually equipped with two pistons, placed in line in the same bore. One cylinder builds up pressure, pushing the second one forward until it also builds up pressure, creating a pressure balance in both circuits. Should the first circuit fail, the first piston will hit the second one and push it forward to create pressure in the second circuit. Should the second circuit fail, the second piston will hit the end of the cylinder, then providing the resistance for the first piston to build up pressure between them. A pressure differential switch between the two circuits will detect such a failure.
A master cylinder is a key component in the most important safety system of a car. Reliability is one of its main demands. That means the cylinder and piston should be made out of high quality metals, offering excellent corrosion resistance even when in contact with corrosive, hygroscopic brake fluid. Manufacturing tolerances and surface roughness should be determined meticulously to ensure smooth operation and low wear. The rubber seals, finally, should also be durable, tear resistant and resistant to brake fluid and ageing.
It takes a lot of expertise to make a high quality master cylinder. Nipparts acquired this expertise over the years and keeps developing its knowhow. This way Nipparts can offer durable and reliable master brake cylinders in OE matching quality. Nipparts master brake cylinders are available for most Japanese and Korean cars.
Nipparts master cylinders:
- Perfect operation due to high precision manufacturing
- High service life due to high grade materials
- OE matching fit and finish