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Can I Put WD40 on My Brakes? | What You Need to Know

Squeaky or squealing brakes can be annoying, to say the least. Since it is common knowledge that WD40 is a lubricant that can remove these noises from door hinges, it makes sense that it might also work to cure this issue with brakes. I have worked for a repair shop, and we dealt with many issues, so I can give you a definitive answer.

WD40 should not be put on your brakes since it can reduce friction where it is needed and even break down and damage brake components. While spraying WD40 may temporarily reduce a brake squeal or squeak, it could also cause the brakes not to function correctly when you need them most.

Brake shims, like these found on Amazon, are something you may want to try to reduce the noise made by brakes.

Let’s cover the reasons to avoid putting WD40 on your brakes in greater detail. I’ll also point you in the right direction on how to deal with squeaks.

WD40 Spraying

Reasons to Not Use WD40 on Brakes

Your brakes consist of multiple components, including a master cylinder, brake lines, caliper, brake pads, and rotor. Spraying WD40 on any of these parts can be harmful. Ultimately, it would likely cause a dent in your pocketbook when you have to replace the parts damaged by WD40.

There are many reasons why WD40 should not be spread on your brakes. The top 3 reasons include:

1. Car Failing to Stop on Time

WD40 works as a solvent. Its primary purpose is to dissolve rust. People often think cleaning the rust off their brake rotors is a good idea; however, doing so can have dangerous consequences. Not to mention, most of the time, the rust will just fall away naturally when you drive.

While WD40 is not a true lubricant, it has lubricating properties. Spraying WD40 on your rotor will cause it not to function properly. When you use WD40 on your brake rotor grease, it is left behind. Oil on the rotor could result in your car not stopping when needed. This could lead to car accidents and injuries, especially if you are unaware of the risk of using WD40 on your rotors.

2. WD40 Can Cause Caliper Corrosion

When WD40 comes in contact with the brake caliper, the dust boot and the piston seal can swell. The dust boot and piston seal becomes soft. They begin to break down.

Here are the potential consequences that can occur:

  1. WD40 corrodes the piston seal and causes the piston to stick. This corrupts the piston’s ability to function as it should. Brake pads will wear down, causing the seal to overheat. The seal will begin to leak and eventually quit working.
  2. When the car is in use, the swollen dust boot can fall apart, causing water to slip into the piston bore. This can result in a piston seizure. This damages the piston and the cylinder. When a piston goes bad, your car can lose power and fail to accelerate properly.

3. WD40 May Destroy Brake Pads

WD40 is not a cleaner. It will not clean your brake pads because it is essentially an oil, and oil should never be applied to a friction surface. Brake pads employ a friction surface, so if you spray WD40 on them, you would have to replace or clean them.

Important Warning: Spraying WD40 on brake pads can ultimately compromise their integrity. Your brake pad’s job is to stand between the brake shoe and the brake drum and provide friction to stop the car. Spraying this substance on them will cause them to wear away and erode the friction surface. And, without functioning brake pads, your car’s brakes could fail. Yikes!

Related 6 Handy Alternatives to WD40.

How Do I Get My Brakes to Stop Squeaking or Squealing?

Closeup of Brakes on a Red Bicycle

Sometimes your brakes will squeak when your brake pads are wearing down. If it has been a while since you last had them changed, you may want to set up a service appointment and get them evaluated for a potential replacement.

And, if you have replaced them recently, a new brake system can be squeaky as well. You can fix this by applying brake grease to key contact points on the caliper. Apply it to the backside of the brake pad. Just keep in mind that it is crucial that no grease gets on the friction side of the brake pad. If you have no training servicing brakes, I recommend not touching them. It’s not worth the risk.

You can also reduce brake noise by adding some shims to the brake pads. This will stop the brake pads from moving around and causing noise. A small rubber layer in the shim helps neutralize any vibrations causing the noise.

Can I Put WD40 on Bike Brakes?

WD40 should not be put on bike brakes, just as it should not be put on car brakes. It can reduce friction and break down the contact points, causing the brakes to not work well or fail completely.

WD40 can be used on other bike parts. However, it should only be sprayed on internal metal bike parts before the parts are put together.

How to Remove WD40 From Bike Brakes?

Accidentally getting WD40 on your bike brakes does not mean you have to replace them. There are ways to clean your brakes and eliminate the harmful effects of WD40 on your brakes.

You can remove the rotor disk from your bike and clean it with alcohol or brake cleaner. Make sure to clean the disk well and any holes the WD40 residue could be hiding in.

You can try cleaning the brake pads, but you may end up needing to replace them. Sanding down the brake pads to remove the WD40, wiping off your brake pads with alcohol, or removing any remnants of the solvent by spraying the pad with brake cleaner are three ways to clean brake pads on your bike.

Let your pads dry after using any wet substance to clean your brake pads. Make sure you test your brake pads out to see if you successfully got rid of the WD40.

What WD40 Also Won’t Fix

  • Plastic chairs
  • Bike chains- Although they may help clean and remove grime, if that’s your purpose. Please read this article for more info.
  • Door hinges
  • Firearms
  • Paintball guns
  • Soft plastic toys
  • Gears
  • Musical instruments
WD40 Being Sprayed on a Bike Chain
Only do this if you have learned the correct process for doing so.

Bottom Line

Having issues with brakes is not something you want to DIY fix. Take my advice and let experts who are highly trained take care of one of the most important components of your car. The safety of you and your loved ones is not worth the risk.

I hope this article has been helpful. Thanks for reading!

For more, check out Does WD40 Harm Plastic? | It Depends.