An advantage of 3/16" line over 1/4" is when it comes to bleed the lines. Since the smaller line has less volume, one pump of the pedal will push the fluid faster and farther. So air will come out quicker, saving time and fluid. Also, where lines go up and down there are high spots that bubbles will tend to collect at. With the smaller tubing it is easier to drive these bubbles down and through the lines.
The Jalopy Journal
