How to Remove a Stripped Bolt

Rusted Bolts and Nuts

Dirk Just / EyeEm / Getty Images

Project Overview
  • Total Time: 10 - 30 mins
  • Yield: Remove one stripped bolt
  • Skill Level: Intermediate
  • Estimated Cost: $5 to $40

Stripped bolts are common, and it's easy to strip a bolt even when you don't mean to. Using a wrench that's too large will round off the head. Rusted bolts are tough to remove, even with an intact bolt head. Broken bolts are the most difficult since there's no bolt head to grab. But when you know how to remove a stripped bolt, you'll be able to extract most rusted, broken, and rounded stripped bolts in less than half an hour.

Before You Begin

When removing a rusted bolt or any bolt that won't budge, penetrating oil or heat will break the rust bond and lubricate the bolt for easier removal.

Penetrating Oil

Penetrating oil is specifically meant to loosen bolts and prevent rust. AeroKroil, Liquid Wrench, PB Blaster, and Royal Purple are common penetrating oil brands.

Penetrating oil can be made with fluids found around the home or garage, such as a 1:1 ratio of acetone and automatic transmission fluid or a 10:1 mix of vegetable oil and acetone.


Water displacement liquids like WD-40 or even engine oil can help loosen bolts, though they do not work as well as heat or manufactured penetrating oils.


Heating the bolt with a propane torch is an effective way to remove a rusted bolt. Heat may not always be an option because of safety concerns.

Safety Considerations

Penetrating oils, acetone, and automatic transmission fluid are toxic and should be handled with care. Wear safety glasses and waterproof gloves. Be careful when using a propane torch around items that may ignite. Do not use penetrating oils near an open flame.

What You'll Need

Equipment / Tools

Remove a Rusted Bolt

  • 1 wire brush
  • 1 set closed-end or socket wrench
  • 1 hammer
  • 1 propane torch (optional)
  • 1 safety glasses

Remove a Broken Bolt

  • 1 needle-nose locking pliers
  • 1 standard locking pliers
  • 1 screw extractor kit
  • 1 rotary tool
  • 1 large flat-head screwdriver
  • 1 safety glasses

Remove a Rounded Bolt

  • 1 standard locking pliers
  • 1 bolt extraction kit
  • 1 socket wrench handle
  • 1 safety glasses


All Methods

  • 1 can penetrating oil


How to Remove a Rusted Bolt

Rusted bolts are tough to remove because the iron oxide hydrate deposits on the bolt bond with deposits on the nut or other female threads. Applying penetrating oil breaks the bond and helps to remove most rusted bolts.

  1. Brush Off Rust

    With the wire brush, clean the rust, paint, and corrosion off of the bolt head. Cleaning the bolt head will provide the wrench with a firmer grip on the bolt head. Also, you'll want to remove rust to give the penetrating oil easier access to the shank's threads.

  2. Use a Hex Closed-End or Socket Wrench

    Open-end C-shaped wrenches will not provide the tightest grip on the bolt head. Similarly, tools like Crescent wrenches, locking pliers, and slip-joint pliers are not ideal for gripping bolt heads. If you previously used any of these wrenches or pliers, switch to a closed-end O-shaped (or box-end) wrench. Also, make sure that the wrench has a 6-point (hexagonal) end rather than a 12-point end.


    If the bolt is not turning, do not force the bolt. To avoid rounding the bolt head, stop and move to the next step.

  3. Tap the Bolt Head

    Gently tap on the bolt head with a smooth-faced hammer or a ball peen hammer. Tap straight down or from the side. Regulate the force of the blow to avoid bending or distorting the bolt, which could make the bolt even more difficult to remove.

  4. Apply Penetrating Oil or Heat

    Penetrating Oil: Shake the can of room temperature penetrating oil. Attach the applicator straw, if any. Completely saturate the bolt with the penetrating oil. Gently tap the bolt a few more times. Spray more penetrating oil and let it sit for about 20 minutes.

    Heat: Light the propane torch and heat the bolt for about 30 seconds. Carefully try to remove the bolt. Intermittently tapping the bolt with the hammer may help as well.


    With a low flashpoint of 150°F, penetrating oils should not be used around open flames. Penetrating oil can be applied to a heated bolt, but avoid using heat and penetrating oil at the same time.

  5. Remove the Rusted Bolt

    Fit a hex closed-end or socket wrench over the bolt and turn counter-clockwise.


If you want to remove a rusted nut from a bolt and the nut can be sacrificed, use a nut splitter. Progressively tightening this $20 device will crack open most nuts up to 3/4-inch.

How to Remove a Broken Bolt

A broken bolt is one where the bolt head has snapped off, leaving the bolt shank flush or nearly flush with the top of the nut or work material.

  1. Turn the Bolt by Gripping It

    If the bolt has not sheared off perfectly flush, you may be able to grab a small section of the bolt with pliers to turn it out, at least partially. Needle-nose locking pliers are capable of gripping small amounts of bolt material.

    Turn the pliers to the side. Open the pliers, then tighten the adjustment screw until the pliers can grip firmly. Close the pliers with the handles. Turn counter-clockwise until about 1/4-inch of the bolt emerges. Then switch to regular locking pliers and turn the bolt the rest of the way out.

  2. Use a Screw Extractor Set

    With reverse-threaded bits, a screw extractor set can remove broken bolts.

    Apply a drop or two of thread-cutting oil. Drill a pilot hole in the center of the bolt. Drill perfectly plumb about 1/4-inch or deeper, if possible.

    Switch to the screw extractor. The extractor bits may either fit into a T-shaped handle for manual removal or they may be chucked into an electric drill. Turn the extractor counter-clockwise until the bit reaches the bottom of the pilot hole. The bolt will begin to emerge. If the extractor bit's grip is still solid, continue turning out the bolt is out. If the grip is weak, switch to a set of locking pliers.

  3. Create a Groove in the Bolt

    Attach a metal-cutting tip to a rotary cutting tool like a Dremel. Holding the tool to the side, groove the top of the bolt head. Be careful not to continue down to the bolt shank. With a flathead screwdriver, turn the bolt out as if you were turning out a slotted screw.

Screw Extractor Kit vs. Bolt Extractor Kit

Screw Extractor Kit: Meant for bolts that have no bolt head left.

Bolt Extractor Kit: Meant for bolts with a portion of head left that can be gripped by the extractor sockets.

How to Remove a Rounded Bolt

A rounded bolt is one where the bolt head is intact but its flat sides and corners have been rounded down, usually from overturning with an improper tool. These can be removed with locking pliers or a bolt extractor kit.

  1. Use Locking Pliers

    Hold a pair of standard locking pliers to the side. Turn the adjustment screw on the pliers so the teeth grip the rounded bolt head with maximum force. Lock the pliers. Turn the bolt counter-clockwise until enough of the bolt is exposed to switch the pliers to a lower section of the bolt.

  2. Use a Bolt Extractor Set

    A bolt extractor set has reverse-spiral sockets that fit over the top of a rounded bolt, gripping the rounded portion so the bolt can be turned out.

    Apply penetrating oil to the bolt. Place the socket over the bolt head. Tap the socket down with a hammer. Fit the socket wrench handle onto the extractor socket. Turn counter-clockwise until the socket grips into the metal and the bolt turns out.

  3. Create a Groove in the Bolt Head

    If the bolt head is rounded or flat by design—like a carriage bolt or button head bolt—grooving a slot and removing it with a screwdriver is the best option.

    With the metal wheel in the rotary tool and the tool held sideways, create a groove in the bolt head large enough for a flathead screwdriver. Add some penetrating oil as a lubricant. Then, turn the bolt out with the screwdriver.

Tips to Avoid Stripping or Breaking Bolts

  • Use a wrench size that correctly corresponds with the bolt size.
  • Avoid mixing Imperial and metric wrenches and bolts.
  • Avoid turning the bolt with adjustable wrenches.
  • Use hexagonal wrenches or sockets to avoid rounding the bolt head.
  • Keep the bolt free of rust by covering it, painting it, or applying penetrating oil.
  • How do you remove a stripped bolt head?

    When the bolt head is stripped or rounded, first try grabbing the bolt head sideways with a pair of locking pliers and turning counter-clockwise. A bolt extractor set is another good option since it has socket-type extractors with internal threads capable of biting into rounded bolt heads.

  • How do you loosen a bolt that won't budge?

    Using penetrating oil is one reliable way to loosen a bolt that won't budge. Applying heat from a propane torch is another way to loosen a bolt.

  • Will heating a bolt loosen it?

    Heating a bolt often will loosen it. With rusted bolts, applying heat from a propane torch for about 30 seconds opens fissures in the rust, allowing the penetrating oil to soak in. With a bolt that is not rusted, heat can still help. The differences in contraction rates between the bolt and the nut produces a gap large enough for the bolt to be turned out.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. How to Make Penetrating Oil. Drexel University / Engineering for Change

  2. Premium Automatic Transmission Fluid SDS. Ford Motorcraft

  3. How Rust and Corrosion Work. ThoughtCo