Originally Posted By: exranger06
Just because steel is more "durable" doesn't mean it's the best choice for the application. Just how durable does the line need to be? Going with that logic, the line should be 1/4" thick wall tubing because it's more durable. Who cares that it's ridiculously thick, expensive, hard to install, etc?
This reminds me of when I replaced the metal gas tank in my Bronco with a plastic one. Even though the plastic is less "durable," it is plenty strong enough to hold gas in it, just about all cars nowadays have plastic tanks and they work just fine, and best of all, the plastic one won't rust like the metal one did (which is why I needed to replace it). In that case, plastic is clearly the superior material.
Flares on aluminum lines can be real problematic, they gall and crack easier if your not very careful, there is also the issue of corrosion between the line and steel fitting. For these reasons they are not as good or as durable as steel.
Neither is as good a SS but that going over the top. NiCopp would be a excellent choice for its ease of bending and corrosion resistance, flares are also not an issue, it is much more malleable than aluminum.
Edit: Neither NiCopp or aluminum should be used on any vehicle used commercially or off road, they are too soft and damage easily.