How to Adjust Disc Brakes

Bike brakes are used very frequently. Being used so frequently, the bike brakes need regular servicing and adjustment. The brakes always have to be perfect to avoid any fatal accident. If your bike brakes do not function properly, it would be very difficult for you to maintain a balance and control on your bike. Now a days there are disc brakes in almost all bikes. These brakes give you a better control using the hydraulic braking mechanism, disc brakes helps you to apply brakes in a fraction of a second without hurting yourself or your bike. The disc brakes require little servicing, which you can do yourself if you know how to adjust disc brakes. Even the mountain bikes have these brakes, and knowing how to adjust disc brakes will help you know how to adjust mountain bike brakes as well.

Equipments required to adjust disc brakes:

  • Goggles or Glare to cover your eyes
  • Hex Head Socket Set
  • Work Gloves
  • Allen Head Socket Set
  • Brake Pads
  • Flat head screwdriver
  • Brake Fluid
  • Combination Wrench Set
  • Clean rags
  • 1/4″ clear plastic hose
  • Bucket

How to adjust disc brakes?

  • Before starting any adjustment you need to clean up the calipers of brake. Spray the brake cleaner on these calipers and then wipe this liquid immediately from the caliper using a rag. This will clean up all the oil and dirt, and make the parts more visible.
  • Now check for the mounting bolts, which hold the brake caliper and lower bracket together. Using the appropriate hex head socket or Allen Wrench, you need to break the torque, which is located on a pair of bolts.
  • Unscrew the bolts and get the brake caliper out from the rotor.
  • Next step is to unscrew the bolts that hold the caliper and brake pad together. You need to pull the mounting clips and brake pad out from the caliper.
  • Now on the interior side of the caliper, spray brake cleaner, and wipe it off at that moment. Inside the caliper, there are pistons. Check if there are any damages on it that would not let the piston function properly.
  • When you open the new brake pads, they are not assembled. You need to put the mounting clips on it and assemble it. After assembling, place it on the caliper. The bolts of the caliper should pass through the caliper and mounting clips, and tightened properly.
  • Next step is placing the brake pads in the piston. If you find it difficult to place it on the piston, slide in a screwdriver that will help the piston open completely, and then you can slide the pads in it.
  • Now again place the caliper on the rotor and lower bracket. Place the mounting bolts as they were, and tighten it completely.

This does not complete the brake adjustment. There is one more part to it, and it is working with the brake fluid. Follow the steps given below to rinse out the brake fluid.

  • Pour a little fresh brake fluid in the brake master cylinder. You can clearly see a difference in the fresh and old or contaminated liquid.
  • There is an ‘air bleed valve’ on the caliper. To this valve, attach the plastic tube mentioned above in equipments. One end of the tube should be attached to the valve, and other end should be in a container or bucket.
  • Now you need to maintain a pressure in the brake line by pulling the brake lever. Using wrench open the bleed valve only by half turn. The fluid will start flowing through the tube, and the brake pressure will start reducing.
  • Now close the bleed valve and release the lever. Repeat this procedure until all the contaminated fluid is cleared from the cylinder.
  • Fill the cylinder again with fresh brake fluid now.
  • If any brake fluid has spilled over the plastic hose or below it, clean it immediately.
  • Tap the entire brake line, up to the cylinder, to get rid of any air bubbles in the entire line. This will block the flow of liquid.
  • Fill the master cylinder again if needed, place the cover, and to check the pressure of the brake line, pull and release the lever a couple of times.


  • In order to empty the fluid from the cylinder, there are suction pipes or tools available, which are used for this purpose. You can check out if you get one.
  • The old fluid can be recycled at any auto parts outlet. Check for any such outlet in your vicinity, and recycle the fluid.
  • If you are doing all this for the first time, it is advisable to take help from some expert or professional.


  • The brake pads should be checked properly. Also, before taking your bike on the road, check the brakes by a small ride in your parking lot or at a place where there is no traffic.

Related Content:

  1. How to Adjust Caliper Brakes
  2. How to Adjust BMX Brakes
  3. How to Adjust Cantilever Brakes
  4. How to Adjust Drum Brakes
  5. How to Stop Brakes from Squeaking

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