Oh crap, I won't be driving the Jeep any time soon then, but that doesn't matter anyway because now I'm having engine problems (going to making another thread for that).

Are these hoses leading to the master cylinder or just in the engine bay?

 

there are 2 rubber hoses, one to each front caliper, and one for the back, they are inexpensive

I dont think a new MC is very expensive ($87 on US ebay)..used ones are advertised for $30, cant see any rebuild kits
the problem you are having shouldnt be caused by a metal line, although its very slightly possible one may be somehow restricted internally, due to crushing and or corrosison