Has anyone ever thought of running steel brake lines in rubber fuel line to prevent the lines from rotting out..... I wasn't sure if it would be worth it

 

I just went with Braided Stainless, best of both worlds and made a huge difference in pedal feel. I got mine from the link below, they can be had cheaper but brakes are one for those things I don't mind spendin extra to know they are quality.
EGR Performance Brakes, brakes for Dodge, Ford, Chevy, GMC, Tahoe, Yukon, Excursion, Dakota, Durango or whatever you drive.

 

On the coast in texas we make em out of small stainless tubing you just have to make your own adapter for the end were it goes into the cylinder. Its alot of work but the truck will rot away before the brake lines do

 

I thought about it using shrinking tube- but if moisture gets in between the tube and the shrinking-it will never get out again.

So the stainless steel solution is something to think about in the long run!

 

Stainless! Wrapping rubber just traps the moisture and causes rust faster. Also note that many brake lines rust out from the inside due to water retained in the brake fluid. Gotta change the brake fluid once in a while, just like any other fluid on a vehicle.

Oh, and don't go upgrading to different spec fluids (like swapping DOT 5 for DOT 3, for instance). Brake fluids are not higher or lower performing depending on the number, they are different chemical formulations and they don't mix AT ALL. If your truck specs DOT 3, just use a good grade of DOT 3.

For some flexible lines, check out any Parker store. They can make custom lines in several materials that are DOT safe. I'm not a big fan of the typical SS braided lines. I've seen too many of those come apart on off-road rigs. Parker has better choices, and they're even in color.