the brake line that needs replaced is laying in between the frame and the gas tank. i dont know whether to take the bed off or just move the gas tank

 

that should have been a steel brake line. it's going to be a real bear to replace it no matter
what you do because if you move the fuel tank you may not be able to disconnect the filler tube and lifting the bed you may not have enough room between the tank and the frame rail

 

just cut the line at both ends and use a piece of new line and 2 compression fittings ! i did that several times and it won,t leak if you get the fittings tight enough !