Brake flex hose is designed to transfer hydraulic force from the car frame to the brake caliper, wheel cylinder or junction block. Brake flex hoses are also used on some hydraulic clutch systems. The purpose of a flex hose is to allow movement of the suspension and steering systems of the car. These components move as the car is being driven over bumps and as steering action is performed. These brake flex hoses are constructed with specialized rubber, reinforced with nylon. Some brake hoses include a Teflon tube used as an inner liner for added strength. All brake flex hoses should be inspected whenever a car service is performed.

If brake fluid is present at any part of the brake flex hose it should be replaced immediately. Once the brake hose been replaced follow normal brake system bleeding procedures. These hoses are connected at either by a double flare fitting and a copper sealing ring. It is recommenced that the copper sealing washer be replaced anytime you disconnect or reconnect a brake flex hose. The double flare does not need to be replaced when service is performed, but the flare does need to be clean before re-assembly. It is recommended using a semi boxed end wrench (flare nut/line wrench) when servicing the brake flex hose. This wrench is made to grab the fitting more efficiently to avoid stripping the hex fitting. [Source: Qingdao Gofar]