How To Loosen Those stubborn Rusted Bolts

Rusted bolts can be a frustrating and challenging problem for anyone who needs to loosen or remove them. Bolts become rusted when they are exposed to moisture, especially if they are made of iron or steel. Rust is formed by the oxidation of the metal, which can cause the bolt to become corroded and weakened over time.

Once a bolt is rusted, it can be extremely difficult to loosen, even with the right tools and techniques. This is because the rust can create a tight bond between the threads of the bolt and the threads of the nut or other mating part. That makes it difficult to break that bond and turn the bolt. In some cases, rusted bolts may even break or strip making removal even more challenging. In this context, understanding the causes and challenges of rusted bolts is essential for anyone who needs to work with metal fasteners, particularly in industrial, mechanical or DIY settings.

There Are Various Ways to Loosen Rusted Bolts and Nuts

There are several effective ways to loosen a rusted or stubborn bolt or nut. Here are some techniques you can try:

  1. Penetrating oil: Applying a high-quality penetrating oil to the bolt can help to loosen rust and corrosion. Allow the oil to soak into the threads for several hours or even overnight before attempting to turn the bolt.
  2. Heat: Heating the surrounding metal can help to expand it and break the bond between the bolt and the mating part. Use a propane torch or heat gun to apply heat to the area around the bolt, being careful not to overheat or damage any nearby components.
  3. Impact wrench: An impact wrench can deliver sudden, powerful bursts of torque that can help to break a stubborn bolt loose. Use a socket that fits snugly on the bolt and apply the impact wrench in short bursts.
  4. Bolt extractor: If the bolt is completely stuck and won’t turn at all, a bolt extractor may be necessary. These tools are designed to grip onto the bolt and provide extra leverage for removal.
  5. Combination of techniques: In some cases, a combination of techniques may be necessary to remove a stubborn bolt. For example, you may need to apply penetrating oil and heat before using an impact wrench or bolt extractor.

The effectiveness of different techniques for loosening stubborn bolts and nuts can vary depending on the specific situation and level of rust or corrosion.

Remember to use caution when attempting to loosen a rusted or stubborn bolt, as excessive force or improper techniques can cause damage to the bolt or surrounding components. If you’re unsure of the best approach, it may be best to seek the advice of a professional or experienced mechanic or handyman.

I Cannot Loosen the Bolt…Now What?

Some bolts may be too damaged or corroded to be loosened, and attempting to force them may cause damage to the surrounding components. In these cases, it may be necessary to cut the bolt or use other specialized tools. If you’re unsure of the best approach, it may be best to seek the advice of a professional or experienced mechanic.

Here are the steps for cutting a bolt or nut off:

  1. Determine the best cutting tool: Depending on the size and location of the bolt, different cutting tools may be used, such as a hacksaw, reciprocating saw, angle grinder or rotary tool with a cutting wheel. Select a tool that is appropriate for the job.
  2. Prepare the work area: Ensure the work area is well-ventilated and clear of any flammable materials. Wear appropriate personal protective equipment, such as eye protection and gloves.
  3. Cut the bolt or nut: Use the cutting tool to carefully cut through the bolt or nut. If possible, cut in a straight line and avoid cutting into the surrounding material. If the bolt or nut is located in a tight or hard-to-reach area, use a cutting tool with a flexible blade or extension.
  4. Remove the bolt or nut: Once the bolt or nut is cut, use pliers or a wrench to remove any remaining pieces from the surrounding material. If the bolt or nut is still stuck, you may need to use a bolt extractor or other specialized tool to remove it.

Cutting off a bolt or nut should be done with caution, as the cutting process can generate heat and sparks that can be dangerous. It is also important to be aware of any nearby electrical or hydraulic lines that could be damaged during the cutting process. If you’re unsure of the best approach or do not have the necessary tools, it may be best to seek the advice of a professional or experienced mechanic or handyman.

What Are the Best Penetrating Oils to Loosen Bolts and Nuts?

There are many different penetrating oils available on the market, but here are some of the most effective ones:

  1. PB Blaster Penetrating Catalyst: This is a popular and well-known penetrating oil that is highly effective at loosening rusted or frozen nuts, bolts, and other metal parts. It contains a powerful formula that is designed to quickly penetrate rust and corrosion, making it easier to remove stuck parts.
  2. Liquid Wrench Penetrating Oil: This is another popular choice that is known for its strong, fast-acting formula. It can penetrate deep into rust and corrosion, breaking the bond between stuck parts and making them easier to remove.
  3. Kroil Penetrating Oil: This oil is known for its ability to penetrate even the tightest spaces and crevices, making it ideal for hard-to-reach bolts and nuts. It contains a proprietary blend of solvents and lubricants that work together to loosen rust and corrosion.
  4. AeroKroil Penetrating Oil: This is a specialized version of the Kroil penetrating oil that is designed for aviation use. It is highly effective at breaking down rust and corrosion, and is often used in aerospace and military applications.
  5. Sea Foam Deep Creep Penetrating Oil: This oil is designed to penetrate deep into rust and corrosion, making it ideal for stuck bolts and nuts. It is also a lubricant, so it can help to prevent future corrosion and rust from forming.

It’s important to note that different oils may work better for different situations, and there may be other penetrating oils that are effective as well. If you’re unsure of which oil to use, it may be best to seek the advice of a professional or experienced mechanic.

Is WD-40 a Good Penetrating Oil for Loosening Rusted Bolts and Nuts?

Because WD-40 is such a well-known lubricant and penetrating oil that is effectively used for a variety of tasks, we thought it might be worth a quick discussion on its effectiveness on rusted bolts and nuts.

WD-40 is primarily a water-displacing spray that is designed to protect metal surfaces from rust and corrosion. WD-40 may be effective for some light-duty applications, such as loosening a mildly rusted bolt or nut that is not excessively stuck. If you’re dealing with a stubborn or heavily corroded bolt or nut, it may be better to use a specialized penetrating oil that is specifically designed for this purpose such as those listed above. That said, WD-40 has specific penetrating oils to choose from for these tougher applications as well.

Whatever penetrating oil you choose, make sure it’s the best one for your specific situation.


Loosening stuck bolts and nuts can be a frustrating and challenging task, especially when they are rusted or corroded. Choosing the right technique and tool for the job will depend on several factors. Those include the location and accessibility of the bolt or nut, the severity of the rust or corrosion, and the size and strength of the bolt or nut. It’s important to approach the task with caution and use appropriate personal protective equipment, as well as seeking the advice of a professional or experienced mechanic if you’re unsure of the best approach.

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