'98 1T brake line replacement/repair?

My '98 1 Ton has blown the rear brake hose that is mounted inside the frame behind the fuel tank. This hose is wrapped in electrical tape, and looks to have been replaced with a longer one. Can anyone advise what is supposed to be there, or the correct length of hose to replace it. Also, what's the easiest way to replace it? Not much room to work in there! Wrench sizes? Shouldn't this be a steel line?

Since it's something as critical as brakes, a trip to your local dealer should get you what came on the truck new.