Bleeding Hydraulic Disc Brake
If the brakes feel soft or slow to respond then the hydraulic disc brake system needs to be bled. It is also necessary to bleed the system after you have opened the system to the air. Such as when shortening the hydraulic hose.
Place the bike in a stand (if available). Position so that it sits parallel to the ground.
Remove brake pads to avoid contamination during the bleed process. (click here to see how to remove brake pads if you are uncertain) ((Insert link to brake pad changing article)) If the brake pads become contaminated with oil the braking performance will be greatly impaired and could possibly lead to
Once the brake pads are removed insert a piston holder tool and push the pistons back into the caliper. This ensures that the pistons will not move inward during bleeding process.
Next, use a T15 Torx wrench to screw out the bolt at the caliper bleed port.
Attach a section of plastic tubing with knurled silver bleed fitting to your syringe (supplied with bleed kit). Fill Syringe halfway with Tektro Mineral Oil. Hold the Syringe vertically with the tip up and tap out any air bubbles. Attach the syringe and tube to the caliper bleed port by turning the knurled silver bleed fitting into the caliper bleed port.
Use a T15 Torx wrench to remove the reservoir bleed plug and set it to the side.
Turn the knurled silver bleed fitting (supplied with the bleed kit) into the reservoir bleed port. Firmly attach a long plastic tube over the bleed fitting and place the other end into a clean dry bottle.
1. TEKTRO Bleed Kit for Hydraulic Disc Brake System
2. T15 Torx wrench
3. Tektro brake fluid (mineral oil only)
4. Piston holder (bleed block)
5. A clean empty bottle
6. Cleaning towel
Start filling the brake with new mineral oil by slowly pushing the syringe. Air bubbles may come out of the reservoir. Continue pushing fluid until you no longer see bubbles coming out of the tube.
Once all air bubbles are removed from the system remove the tube and knurled bleed fitting from the brake lever reservoir. Re-install the T-15 reservoir bleed plug and tighten to 2-4Nm. Once the bleed plug is installed at the reservoir, you may now remove the syringe and knurled bleed fitting from the caliper.
Then re-install the T-15 caliper bleed plug and tighten to 2-4Nm.
Wipe off any excess oil from the lever and caliper body to ensure there is no risk of contaminating the brake pads or rotor. If oil has contaminated the rotor clean the rotor using isopropyl alcohol. Then remove the piston holder tool and re-install the brake pads.
If you are not confident in your ability to successfully and safely perform all steps, we recommend having the work performed or checked by a local, certified, and reputable bike mechanic.