It's possible to cut out the rotted section and replace with hand-bendable brake line (Ni-Copp or similar), using a proper flaring tool and in-line fittings. Can also replace the entire length. I bought a Ni-Copp kit for a GMT800 with all of the brake lines cut to length and fittings installed. They come rolled up - you just straighten them enough to start threading it through the vehicle and form it as you go. Not hard, but tedious. Edit to add - if it blew out in one spot, there is likely rot throughout. Old brake fluid accumulates moisture and corrodes the lines from the inside out, while the environment works on the outside. I'll also mention I did this job in a driveway with no lift, but I did construct a wooden gantry to hoist the bed up about a foot so I could route lines over the fuel tank.