Genuine AP rear hose. We all believe that our life often depends on our braking system. But how can you tell when "it's good enough"? The flexible rubber brake hoses are a prime area for concern. The hose is exposed to both road grime (rain and dirt) and also constant flexing from suspension movement. While they are normally very thick, visible cracking should raise an alarm. This is typically caused by the elements but should be viewed as a indication of age. Of equal concern is the inside of the hose. While there is no way to inspect it, an old hose actually swells up inwardly, often reducing the area that the fluid flows through to half or less. The best precaution is preventive maintenance. If you can see cracking on the outside replace them.