1/2 inch (13mm) brake servo hose is a component of a vehicle's brake system that is used to transfer brake fluid between the brake master cylinder and the brake calipers or wheel cylinders. The brake servo hose is a flexible, high-pressure hose that is made of a durable material such as rubber or synthetic rubber. It is designed to withstand the high pressures and temperatures generated during braking, as well as the harsh conditions encountered in a vehicle's environment.

The brake servo hose connects to the brake master cylinder on one end, and to the brake calipers or wheel cylinders on the other end. When the driver applies the brakes, brake fluid is forced out of the master cylinder and into the brake servo hose. The fluid then travels through the hose to the brake calipers or wheel cylinders, where it is used to apply pressure to the brake pads, which in turn slows down or stops the vehicle.

The 1/2 inch (13mm) size of the brake servo hose refers to the diameter of the hose. It is important to use the correct size of hose for your vehicle's brake system, as using a hose that is too small or too large can cause problems with brake performance and reliability. For example, using a hose that is too small can cause the hose to become restricted, which can reduce brake fluid flow and lead to poor brake performance. On the other hand, using a hose that is too large can cause the hose to become too flexible, which can result in brake pedal travel that is too long and reduced brake force.