Creating a brake with power and the right feel was the challenge. Hayes has done this by creating a completely new system. The master cylinder of the Hayes Dominion A4 brake is factory-set for the shortest possible dead travel and a clean point contact. The Dominion A4 brake caliper uses four pistons in the most rigid design possible. It features a cold-forged caliper and a KingPin pad retaining screw for added rigidity. With a motorsport-inspired two-port bleed system, DOT 5.1 fluid and Kevlar hose, the hydraulic system is designed for optimum performance in all temperatures and for easy, efficient maintenance.