How to Clean Mountain Bike Disc Brakes

I spilled a little chain lube on my mountain bike’s rear disk brake when I was prepping it for an afternoon ride. I did not realize it at first but, as soon as I started riding I discovered my rear brake was not working. I wrote this guide to help anyone else who is looking for a ways to clean their mountain bikes disk brakes.

Cleaning Mountain Bike Disk Brakes

Cleaning mountain bike disk brakes is done by removing the wheels, wiping disc brakes with a clean rag and brake cleaner or isopropyl alcohol. To tune the brakes up even more scuffing up both the pads and calipers with fine sandpaper, and finally reinstall and bed them in.

How to Determine the Type of Brakes your Mountain Bike Has

There are four main types of mountain bike breaks: V-Brakes, Cantilevers, Caliper Brakes, and of course Disk Brakes. All of these provide advantages and disadvantages to different riders with different needs. However, the most common type of brake for a mountain bike to have are disk brakes. Determining if you have disk brakes is very simple and should not take more than a glance at your mountain bike.

If your mountain bike has disk brakes then you will see a smaller circle around the center of your mountain bike’s tires that will be metallic and have a small brake caliper attached where the brake pads are located. It will look something like this…

There are two main kinds of disk brakes that exist today and depending on which kind you have this will change the disassembly and reassembly process slightly. The first kind are the older mechanical brakes that use a normal lever connected to the caliper by a cable. The second are the newer style hydraulic brakes that use a lever connected to the caliper by a hose which contains incompressible hydraulic fluid. Hydraulic brakes are much stronger and much more responsive… but also more expensive and costlier to maintain.

Luckily enough telling whether or not you have mechanical or hydraulic disk brakes is really easy. On a mountain bike with mechanical breaks somewhere on the break caliper you will be able to see the actual wire which is connected to the caliper itself. On a mountain bike with hydraulic brakes you will only see the hydraulic tube going into the caliper itself.

As a safety note. Stopping and trusting your brakes is important. If you have the slightest doubt about how affect your brakes are. PLEASE take your MTB to a reputable bike shop and have them brakes inspected.

How to Remove Both Mechanical and Hydraulic Disk Brakes

Necessary tools include…

• Needle nose pliers 
• Appropriate screwdriver, hex or Torx compatible wrench
• Tool with a flat surface for pressing in hydraulic pistons (if your disk brakes are hydraulic)

If you want to see the AWESOME Mountain Bike Tool Kit, I’ve been assembling read this article. Best MTB Tool Kit I’ve been surprised that by getting little kits of tools I’ve gathered everything I need to build an MTB.

Steps to Remove Wheel and Disc Brakes

The first step to cleaning your disk brakes is to remove the brake pads and disk itself.

Removing the brake pad starts with placing the mountain bike on a stand and removing the wheel.

Once the wheel is removed, remove the brake pads themselves by the method appropriate for the style brake caliper your bike has.

• Pin style: For pin style brake calipers use the needle nose pliers to pull the pin out (you may have to bend the opposite side inward) and then use the head of the pliers to push them out. Be sure not to lose the pin while you’re cleaning!
• Spring style: for these simply use the pliers (or even your fingers) to compress the pads and then pull them through the back of the caliper to remove them.
• Magnet style: For these simply pull them out with the pliers from the front of the caliper (Note: often these are used in conjunction with a retaining pin).
• Clip style: Again, simply pull them out with the needle nose pliers (This may require a bit of force to remove the clips).

The next step is to remove the disk itself. To do this remove all of the torque screws which are holding it to the frame.

How to Clean Mountain Bike Disk Brakes

Necessary Tools and Materials Include…

• Automotive brake cleaning fluid is best (Or, less ideally, isopropyl alcohol)
• Nitrile or latex gloves.
• Fine wet/dry sandpaper above 1000 is best
• Clean lint-free shop towels

The first step is to place the brake pads and disk on a bed of lint free shop towels and put on some nitrile or latex gloves (the kind that doctors wear). This is to prevent any oil transfer onto the brakes.

The next step is to use a good motorbike disk brake cleaner (not regular disk brake cleaner as these sometimes include oils) and spray the brake pad and disk liberally. Wipe away any residue until the brake cleaner completely evaporates.

Now, use some low grit wet/dry metal sandpaper to rough up surface of both the brake pads and the part of the disk which the pads contact. Re-clean them both with the brake parts cleaner after doing this.

Without removing the gloves, re-install the brake pads and disk. Then re-mount the wheel to the bike.

How to Prepare Your Brake Calipers for New or Cleaned Brake Pads

Mechanical Brake Calipers:
Turn the caliper adjustment all of the way to the left (counterclockwise). This releases any tension on the cable system.

Hydraulic Brake Calipers:
Press the pistons back into the caliper body with a flat tool. Remember to never press your brake lever when the wheel is off the bike or you will have to repeat this process.

Checking for any leaks in the hydraulic system near the caliper can help you find the source of any oily substances getting on your brake pads or disk. If any are found it will need to fixed immediately as an improperly functioning braking system can be incredibly dangerous to yourself and others.

How to Tell if Your Mountain Bike’s Brake Pads Need to Be Replaced

Mountain bike brake pads work by creating friction by rubbing together a brake pad and a metallic disk to stop the bike. The brake pad itself will deteriorate over time and cause squeaking or a complete loss in functionality.

A mountain bikes brake pad must be at least 1mm in thickness and so if this condition is not met then they are due to be replaced.

Stacking three regular size credit cards on top of each other replicates about 1mm of thickness. However, calipers should be used if there is any question about the true thickness of the pad. Brake pads can get expensive so it is understandable that you might not want to replace them if you do not have to.

However, if they do not work properly then it is very dangerous to be riding. You do not want to be cutting corners in this area of the maintenance of your mountain bike.

How to Bed-In New Mountain Bike Brake Pads

New Mountain bike brake pads have an initial smooth layer which protects the pad in the time before it is installed on your mountain bike but which also can cause your brakes not work very effectively at first. To maintain a safe and fun experience it is a good idea to bed-in the brakes.

When bedding-in new brakes find a SAFE area with no obstacles or hazards to ride. NO don’t go to the local trail – and empty parking lot is a better choice.

To do this you first install the new brake pads. Once this is done, you then put a small bit of water onto the pad itself. Get up to a moderate speed (5-8 mph) speed on the bike and then cycle the brakes on and off wheel still pedaling. Do this about twenty more times remembering to put water on the pad in-between every time. This will not only take off the initial layer but also clean away the residue which will be produced.