There's two things to consider. First of all, the master cylinder can be damaged when you run the pedal to the floor. This often happens when the system is being bled with a helper. To avoid that, never push the pedal more than half way down unless the master cylinder is less than about a year old. Crud and corrosion build up in the bottoms of the bores where the pistons don't normally travel. When you do push them that far the lip seals can get torn on that crud.
Second, on a lot of ABS systems you need a scanner to activate a couple of the valves to allow trapped air to bleed out. That is not a concern if the brake fluid reservoir never ran empty or if you have the rear-wheel ABS system. The scanner is needed for all-wheel ABS systems.
Tuesday, July 30th, 2013 AT 8:02 PM