Even though they are a pain, always use a double flare on brake lines.
I bet your brake line "gouge" is at the seem where the line was drawn over the mandrel to form the line.
Yes, double flaring tools are a pain in the ass. Yes, a single flare will work more often than it won't. Yes, I hate...
I am working on Geenie GTH1056 telehandler forklift with Spicer 213 axles. I just overhauled one of the axles. It has wet brakes that are lubed by the diff oil. The Spicer/Dana axle manual calls for SAE 80W90, GL4, MIL 1205, with "additives for oil-bath brakes".
My oil distributor (Chevron) is...