Does WD-40 Loosen Stuck Bolts?

Using WD-40 to loosen stuck bolts.

Penetrating lubricants like WD-40 are petroleum-based products that offer deep lubrication for moving parts and help protect against rust and corrosion. In addition, these lubricants help release rusted or seized parts.

WD-40 loosens bolts because it reduces friction between the bolt and the fastener. The bolt slides more effortlessly, making it easier to remove. The viscosity also helps WD-40 loosen bolts because it slips into cracks to reach the threads of the fastener or into cracks to loosen the connection.

Dealing with stuck bolts can add a great deal of time to your projects. In this article, you’ll learn how WD-40 affects bolts to loosen them and how to remove a stuck bolt using this popular multi-purpose lubricant. Read on to learn more, and finally, get that bolt unstuck once and for all!

How WD-40 Affects Stuck Bolts, Screws, and Seized Parts

The “WD” in WD-40 stands for “water displacement,” and the 40 represents the chemical makeup being the company’s fortieth formula.

These water displacement properties are what make WD-40 such an effective product. While most people utilize it as a way to eliminate squeaks or prevent rust, it also helps rid surfaces of corrosion if it’s already taken hold.

This, along with its lubricating ingredients and high viscosity, is precisely why WD-40 is so effective at loosening bolts and why it remains a staple in garages, machine shops, and homes.

WD-40 Contains Lubricating Ingredients

WD-40 consists primarily of petroleum-based lubricants, including naphtha and other oils. It also contains benzenes and mixed isomers, along with carbon dioxide to help propel it from its spray canister. The complete formula of WD-40 has never been released (it is, after all, a protected trade secret).

Lubricants help loosen bolts by reducing friction between the two points of contact. In the case of a stuck bolt, it allows the bolt and the fastener to slide against one another with ease, allowing the bolt to break the surface barrier to come loose.

WD-40 Has a Low Viscosity

The very low viscosity of WD-40 allows it to expel from the canister as a fine mist. The low viscosity also provides an exceptional capillary effect.

Since WD-40 sprays as a fine mist and has great capillary permeability, it moves easily into small openings and can even work against gravity. It slides into the tiniest crevices around the threads of a bolt, even those appearing solid or invisible. Even if the bolt is corroded by rust, the lubricant has no problems sliding into the microcracks to access the metal of the bolt.

How to Remove a Stuck Bolt with WD-40

When attempting to remove a bolt using WD-40, choose only the “penetrating lubricant.” The company makes dozens of other products, but the penetrating lubricant is best for loosening bolts and other seized parts.

After acquiring the product, use the following instructions to remove a stuck bolt with WD-40:

  1. Spray WD-40 directly on the bolt.
  2. Wait at least 30 minutes to give the lubricant time to penetrate the bolt’s threads.
  3. Attempt to loosen the bolt. If it still doesn’t give, move on to step three.
  4. Hit the bolt with some force using a tool, such as a hammer. The impact should create cracks in the rust if there is corrosion build-up.
  5. Spray more WD-40 on the bolt. Wait at least 15 minutes, giving the lubricant time to penetrate the cracks of the rust.
  6. Attempt to loosen the bolt again. If it still doesn’t budge, move on to step seven.
  7. Wash away the WD-40 using mild soap and water (it is flammable). Remove any rubber or plastic parts and set them aside.
  8. Fill a spray bottle with cold tap water.
  9. Use a propane torch and heat the bolt’s head for 15 seconds (do not get it red hot).
  10. Spray the bolt with the cold tap water to cool it off quickly. Continue spraying until the steam dissipates.
  11. Spray more WD-40 on the bolt and wait 15 more seconds before attempting to remove the bolt again.

If the above steps fail, repeat steps one through six until the bolt comes loose (you do not want to overheat the bolt; this can weaken it, causing you to need a replacement).


Dry or corroded surfaces create a lot of resistance due to surface tension. By adding a lubricant, you can reduce friction between a bolt and fastener, making it easier to twist and remove. As an added bonus, using WD-40 also prevents corrosion, eliminating future problems with seized bolts caused by rust.

Scroll to Top