Difficulty: 4/5

This guide will cover installation and adjustment of hydraulic disc brakes (with a focus on Hayes.) Setting up hydraulic discs is very similar to mechanical disc setup, but it’s almost easier since there are no cable adjustments.

You will need:

  • T25 Torx wrench
  • 5mm Hex wrench
  • Torque wrench

1. Install the rotor.

Start by mounting the rotor to the hub using six T25 Torx bolts. Make sure the rotor is facing the correct direction (arrow points in rotation direction.)

Tighten these bolts to the proper torque.

2. Install the caliper.

Mount the caliper and mounting brackets to the disc tabs on your frame or fork (for International Standard (IS) mount.)

Tighten those bolts to the proper torque.

3. Put wheel on bike.

Now you can put the wheel on the bike and tighten the quick release.

4. Loosen caliper.

Make sure that the two bolts holding the caliper to the adapter are loose. If they are tight, you can turn them about 1/2 turn counterclockwise.

The caliper should move freely side to side.

5. Pull brake lever.

Pull the brake lever to the bar and hold it there using either a Velcro strap or rubber band.

(This should cause the caliper to center itself over the disc.)

6. Tighten caliper.

Tighten the bolts that hold the caliper to the adapter.

7. Loosen brake lever.

Now you can remove the band that’s holding the brake lever down.

The lever should spring back, releasing the brake pads from the rotor. There should now be a small gap on each side of the rotor.

8. Ride.

Now the brake should be working fine, so you can ride!

(The brakes should have come with pre-bled lines. If not, you will have to bleed the brakes before use.)


The tools for this repair can be purchased at:

Performance Bike, REI, or eBay.