If I recall correctly the two rear lines going from the cylinders to the axle "T" are 1/4". Making the bends where they go around the end of the axle and into the cylinder is tricky. From the axle "T" up to the frame union should be a rubber flex line, then 3/16" up along the frame to the front "T". Some brake lines come with a short and long tube nut, it really doesn't matter which end they go on but I would use the short nut on the wheel cylinder just for clearance. If you are not that excited about making your own brake lines there is a company that makes a stainless set for the M715, just google M715 brake line set.