my passenger stainless steel brake line began to rub on my axle. some of that rubber insulation wore off. so is there a method to add that clear rubber insulation back??

 

Just get the line back out of the way and secure it.

The only thing that comes to my mind that could possibly work would be the "wonder dip" that you can dip you plier handles in it makes a coat on it like a bed liner. Just try to brush it on. Or try the spray in bedliner, but i would think with the dip you could get a better coat on it.