Any discussion of hydraulic system bleeding usually includes a debate about which method is better: the master cylinder push-through or the vacuum tool suck-through. While many mechanics will subscribe to either one or the other, I've found a combination of the two works best. When bleeding dry lines, nothing gets them primed quicker than a vacuum bleeder. However, when swapping fluid, I prefer the pump-through method. So, when installing new lines, I use both methods. First, draw the fluid through with a suction tool, followed by the final flushing of air with the master cylinder pumping method. Regardless of which technique you incorporate, the goal is to fill the system completely with fresh hydraulic fluid and no air bubbles. You'll be glad you did this the next time you grab a handful of brake.