What Is a Brake Hose?
A brake hose is a hose that conveys brake fluid to the wheel brake cylinders.
It transmits the hydraulic pressure of the brakes to the wheels and stops the vehicle due to friction between the disc or drum on the wheel side and the brake pads. Rubber hoses are used, but some hoses are covered with stainless steel braid or coated with PVC, which prevents expansion and increases durability compared to rubber.
The structure of a brake hose consists of layers from the inside: inner tube rubber, lower thread layer, intermediate rubber, upper thread layer, and outer skin rubber, all made of different types of rubber. Nitrile rubber is used for the inner tube rubber because it comes in contact with brake fluid. This material has excellent oil and abrasion resistance. The outer rubber layer is made of highly durable rubber with excellent weather resistance.
Uses of Brake Hoses
Brake hose is a hydraulic circuit that connects the master cylinder on the body side to the wheel cylinders and calipers on the wheel side. Wheels are subject to significant displacement in the vertical direction due to the suspension system, and front wheels are also subject to displacement due to steering. Hoses are used to absorb this displacement; four brake hoses are required for a car with four-wheel independent suspension. A two-wheel independent suspension, such as in buses and trucks, requires a minimum of three hoses.
In addition to high displacement, brakes are subject to high hydraulic pressures and high temperatures. This is because brakes convert kinetic energy into heat, and brake hoses are subject to that heat. Brake hoses are multi-layered to withstand pressure, high displacement, and high temperatures.
Principle of Brake Hoses
Since brake hoses are subjected to large displacements, they are made primarily of rubber material to increase flexibility. Genuine parts from automobile manufacturers are rubber brake hoses, but mesh hoses are also used.
Mesh hoses are made of Teflon tubing covered with a woven aluminum or stainless steel outer layer. Rubber hoses expand when subjected to high pressure and repetition, which can gradually deteriorate braking performance, and they are not completely durable. Mesh hoses are more durable than rubber hoses, and the expansion of the hose is minimal, allowing the brakes to continue to perform well.
In automobiles, the force required to apply the brakes is increased by the action of a lever, and then multiplied several times by a doubling device called a master back that uses the engine intake pressure, and the diameter of the cylinder that operates the brakes on the wheel side is increased in relation to the diameter of the master cylinder that generates the brake pressure. The hydraulic pressure at that time is 70 to 100 kg. The hydraulic pressure at that time is about 70-100 kg/cm2, and this hydraulic pressure is also applied to the brake hose.