Air entrapped in the Hydraulic system of the disc brakes can decrease performance of the system and should be removed by bleeding the system and replenishing the system with new brake fluid. The system is filled by pumping fluid from the lowest point (at the caliper), through the system, to the highest point, the bleeder on the master cylinder.

Tools required:

• Brake bleeding kit
• Brake fluid oil (DOT or mineral depending on brake model)
• 8mm Wrench (can sometimes be 6mm depending on brake model)
• 5mm Allen key
• Cloth or paper towels

1. Adjust the Brake Lever and position it vertically so that the Master Cylinder is the highest point on the Brake System. (Image 1)

2. Remove the Bleed screw from the Brake Lever Reservoir. (Image 2)

3. Attach the Fluid bottle to the handle bar in an upright position next to the Master Cylinder using some insulation tape or a Rubber Band.
4. Place the bleed hose firmly into Master Cylinder. Direct the other end of the Bleed Hose into the Fluid bottle. (Image 3)

NOTE: Use the correct Master Cylinder adaptor for your Model of Brakes. Hayes HFX-9 Brakes use an Aluminium adaptor.

5. Loosen the Bleed Nipple on the Brake Caliper and remove it altogether. (Image 4)

6. Screw in the Bleed Valve adaptor attached to the loaded Syringe. (Image 5)

7. Begin slowly compressing the Syringe while watching for air bubbles rising to the top of the Brake System in the clear Master Cylinder hose. (Image 6)
8. Continue bleeding the System until air bubbles stop appearing in the clear hose.
9. Once completed, remove the hose and fitting from the master cylinder. For the HFX-Mag reinstall the master cylinder bleeder screw and rubber washer – tightening until the rubber washer starts to bulge. Caution: Do not over tighten the screw. For the HFX-9, insert the plastic reservoir plug.

10. Clean the Caliper and Master Cylinder with Isopropyl Alcohol. Take great care to remove all brake fluid because if the fluid comes into contact with the disc or brake pads, performance will forever be greatly reduced.
11. Clean the disc with isopropyl alcohol if it is contaminated with oil or brake fluid.
12. Remove the Bleed Valve adaptor from the Brake Caliper and replace the bleed nipple. Place the Rubber Dust cap back on the Bleed Nipple. (Image 7)

13. Mount the Lever and Caliper back to the bike. Pump the brake lever to push the pads to the proper location.
14. Center the Caliper over the disc.
15. Check all hose connections for leakage. Tighten if any leaks are found.