Disc Brake Squeal After Washing Your Bicycle? Solved!

Disc Brake Squeal After Washing Your Bicycle Solved

Were your disc brakes stopping quietly BEFORE you washed the bike, but now squeal when stopping AFTER washing your bike?

Well, I had the exact same problem. After searching around on the internet, I came across the following information regarding proper cleaning of disc brake components;

  1. The disc pads and rotors must not be contaminated by degreasers, aerosols, lubes or even with body oils from your fingers. Any of these contaminants can result in noisy braking and you may need to replace the pads if they are badly contaminated as the pad material can be porous.
  2. It is fine to use bicycle specific washing detergents & disc brake cleaning products or isopropyl alcohol when cleaning the brake calliper, brake pads or disc rotors.

I followed all this advice when washing my bike, BUT I still found that on the next ride, the brakes were still squeaking or squealing – which is really annoying! It got me thinking of ways to solve this problem because I often ride my disc brake bike in wet conditions and I regularly wash it.

After testing various products and washing techniques, I finally discovered a solution which is extremely simple and cheap!

My Solution

1. Use only plain water to wash the brake pads and braking surface of the rotor. Don’t use any cleaning products on the brake pads or rotors when the brakes are working fine.

2. Do NOT wipe the braking surface of the rotor with a sponge, paper towel or a cloth. Preferably don’t touch the braking surface of the rotor at all when washing your bike. In most situations, water from the hose will wash off any grit or contaminants from the braking surface of the rotor.

3. Do NOT wipe the braking surface of the pads. Wash the pads with plain water from a hose. If you are unable to flush out particles, then you may need to remove the brake pads from the calliper, but hopefully you should not need to touch the braking surface of the pads during regular cleaning.

By following these steps when washing my bike, once it was dry, I found the braking to be quiet and perform just like it did before the wash.

So why does wiping a disc rotor clean cause noise?

When you buy a new bike (or replace worn brake pads or rotors) you need to perform a disc brake bed-in which involves riding the bike and applying varying amounts of braking over a number of repetitions. It’s easy to do and an important step in ensuring powerful, consistent and quiet disc braking performance.

During the bed-in process, the disc rotor is coated with a thin layer of brake pad material which creates a nice compliant braking surface. However, when you start wiping the braking surface of the rotor clean, you may inadvertently remove some (or all) of this thin coating of pad material which can lead to brake squeal and poor stopping performance.

My brakes squeal, so how do I fix this problem?

If you did not contaminate your disc brake pads and rotors with chemicals or oils, you may be able to solve this problem by just repeating the disc brake bed-in process (as described in step 3 below). However, I decided to clean and refresh the brake pads and rotors before performing a disc brake bed-in to get the best results.

How to Clean and Refresh the Brake Pads and Rotors

In this article, I will discuss the steps I used to thoroughly clean and refresh the brake pads and rotors. It is a good idea to start with a clean and dry bike and wearing disposable gloves when handling, cleaning and reassembling brake parts. Change gloves as required to ensure pads and rotors are not contaminated during the process. Please read the entire article before commencing any work.

Tools required for this job

  • Bicycle specific disc brake cleaner or Isopropyl alcohol to clean pads, rotors and inside brake callipers.
  • Several sets of disposable gloves.
  • Fine grit sandpaper eg. 800, if you want to refresh the surface of the brake pads.
  • Any tools required to remove brake pads from brake callipers.
  • Very clean lint free rag or cloth.
  • Clean and dry bicycle to minimise dirty fingers.
  • Digital Vernier caliper to measure wear of pads and rotors (if required).

WARNING! The brakes on your bicycle are an important safety component. Please read my disclaimer at the end of this article before attempting any of these steps on your own bike.

1. Begin with the front wheel:

  • Remove the front wheel from the bike.
  • Remove both brake pads from the front brake calliper.
  • Check the pad and rotor wear is within minimum tolerances as specified by the manufacturer.
  • With the brake pads removed, clean inside the front brake calliper.
  • Clean the brake pads on all sides to remove all contaminants.
  • You can refresh the brake pads by LIGHTLY and EVENLY sanding the braking surface of the brake pads using a fine grit sandpaper eg. 800. Place the sandpaper on a HARD FLAT SURFACE. Using light pressure rub the brake pad across the sandpaper a few times. Inspect it and repeat if required. This will expose a fresh layer of pad material. The pad surface will likely change colour having removed the dirty top layer. My Shimano L03A resin brake pads required only a very light sand to remove this top dirty layer.
  • Wipe the brake pads once more with a clean cloth to remove any residue dust.
  • Check the brake pads are still within the minimum wear tolerance.
  • Correctly reassemble the brake pads back into the brake calliper on the bike.
  • Thoroughly clean BOTH sides of the braking surface on the front disc rotor. Repeat cleaning until there is NO dirty residue on a clean cloth. The rotors must be PERFECTLY clean on BOTH sides of the braking surface.
  • Fit the front wheel into the bike.

Explanation of the above images;
A. Front disc brake rotor and calliper on a road bike.
B. Rear disc brake calliper on a road bike.
C. Shimano disc brake pads and spring (they come in many shapes and sizes).

2. Continue with the rear wheel

Repeat the same process to clean the rear brake calliper, pads and rotor.

3. Bed-in the Disc Brakes

Now that the disc brake pads and rotors are clean, the final (and very important) step is to bed-in the brakes. There are many great videos and articles available online discussing this process. Here is a link to the disc brake bed-in video from SRAM. I believe the process is very similar irrespective of disc brake manufacturer.

Conclusion

Hopefully this article has helped you to achieve quiet and powerful disc brakes again. By following these simple washing and handling rules, hopefully your disc brakes will remain that way;

  • Only wash the disc brake rotors and pads with plain water.
  • Don’t touch or wipe the braking surface of the rotor or pads.
  • Don’t contaminate brake pads or rotors with oils, degreasers or body oils from your fingers.

Disclaimer!

Please remember that this information is only to be used as a guide.
I consider myself an enthusiast, not an expert. The information I have presented in this article is based on my own research and experience.

Whilst I enjoy working on my own bikes, I am not a qualified bicycle mechanic. The content of this article is purely illustrative and does not constitute professional advice. For your own safety, any type of work should only be undertaken by a qualified bicycle mechanic. Incorrect assembly of parts could result in equipment damage, personal injury or death.

About Me.

I have been riding and working on my own bikes for many years now. I wanted to share my experiences, knowledge and research with others. My aim is to inspire people to get involved in all aspects of this amazing sport. Cheers.

Comments.

I welcome reader feedback in the comments section. Should you wish to suggest an amendment, please include a note advising the source of your information so that myself and other readers can ascertain the accuracy of your information. Note: Trolling or argumentative comments will be removed as they are counter-productive.

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