Hydraulic disc brakes require periodic bleeding to remove air bubbles and maintain consistent lever feel. The Park Tool BKD-1.2 contains everything you need to bleed DOT-based brake systems from SRAM and Avid, along with Hayes, Formula, and other manufacturers that specify DOT 4 or DOT 5.1 fluid. The kit doesn't include brake fluid itself—DOT formulations have shelf life considerations and different manufacturers sometimes specify particular variants, so Park Tool leaves that choice to you.

The syringe-based system works by pushing fresh fluid through the caliper while drawing old fluid and air bubbles out at the lever. You get two syringes with graduated markings so you can track exactly how much fluid moves through the system. The included tubing connects to bleed fittings on both ends of the brake line, creating a closed loop that minimizes mess and prevents air from sneaking back into the system during the process.

Adapter fittings cover the range of bleed port designs across DOT brake manufacturers. SRAM and Avid use one fitting style at the lever, Hayes another, and the caliper-side connections vary too. The BKD-1.2 includes the adapters for each, so you're not hunting for brand-specific fittings when you switch between bikes or help out a friend with a different brake setup. A bleed block holds the pistons in position while you work, preventing them from extending too far when the pads are removed.... Read More