- Lubricate the bolt with WD-40 and use vice-grip pliers or a long wrench to twist loose. Heat it with a torch for 15 seconds to loosen it more if needed.
- For rust, apply rust-penetrating liquid thread loosener and strike the the bolt 6-12 times with a hammer. Twist loose with a long-handled socket wrench.
- If a screw extractor can’t get the bolt out, cut the screw off with a reciprocating saw.
Loosening a Bolt with a Wrench or Pliers
Spray penetrating oil under the bolt head and around the nut. Penetrating oils like WD-40 will seep beneath the head of the bolt and under the nut and help to lubricate the threading on the bolt. This will make the bolt easier to loosen and will be especially useful if the bolt is rusted in place. Give the oil at least 20 minutes to soak in. Purchase a penetrating oil at any hardware store. You might be able to find it at a large supermarket also.
Slip a hollow piece of metal over the handle of a box-end wrench. Use a piece of metal that’s at least 2 feet (0.61 m) long. This will effectively lengthen your wrench by 2 feet (0.61 m) and will give you more torque when you try to remove the stuck bolt. You can find hollow metal bars at large hardware or home-improvement stores. Look for a bar that has a hollow inner diameter of at least ⁄4 in (19 mm). If you like, bring your box-end wrench with you to the hardware store to make sure its handle fits inside of the metal bar you choose. Be aware that using a hollow bar to increase the torque of your wrench may damage or snap the wrench.
Try to unscrew the stuck bolt with the extended wrench. Hook the end of your box-end wrench around the head of the stuck bolt, and hold the wrench at the very end of the extender bar. With your other hand, grip the nut with a large pair of pliers. Pull sharply on the end of the wrench to try to loosen the stuck bolt. Ideally, the penetrating spray will have weakened the bolt’s resistance so that it loosens. If it’s too awkward to hold both the wrench and pliers at once, ask a friend or family member to help you by holding the pliers.
Use a pair of vice-grip pliers if the bolt or nut are stripped. If the sharp hexagonal sides of the stuck bolt have been stripped and rounded, a box-end wrench will slip off when you try to loosen the bolt. Vice-grip pliers have teeth on the inside of their rounded jaws and can be fastened tightly around the flat surfaces of a stripped bolt. You should be able to slip a hollow piece of metal over the end of vice-grip pliers just as you would over any other wrench.
Heating the Bolt to Loosen It
Heat the bolt with a propane torch if it’s still stuck. If the bolt doesn’t budge when you try loosening it with the extended wrench, it’s time to try using heat to un-stick the bolt. Turn on a propane torch, and hold the flame about ⁄2 inch (13 mm) away from the bolt. Keep the flame on the bolt for about 15 seconds. The heat from the propane torch should cause the bolt to expand.
Apply flame from the propane torch to the nut for 15 seconds. Once you’ve applied the flame to the bolt and it’s begun to expand, switch and heat the nut for 15 seconds. Alternate between the nut and bolt for about 2 minutes total. The end of the bolt that you’re not applying flame to will contract and the end that you’re heating will expand. This will change the overall shape of the bolt. Ideally, the bolt’s expansion and contraction will break whatever corrosion holds it in place.
Loosen the bolt with an extended wrench. Insert the end of your box-end wrench into a hollow metal bar. Hook the wrench onto the bolt and grasp the nut with a pair of large pliers. Hold the nut in position and pull on the end of the wrench. Give 4-5 sharp tugs and see if the bolt moves. If the bolt still doesn’t loosen, heat it with the propane torch for another 10 minutes, or move on to another method.
Removing a Rusted Bolt
Remove as much rust as possible with a wire brush. Take a stiff-bristle wire brush and brush it aggressively against the rust crusted on the stuck bold (and corresponding nut). It’s next to impossible to remove a bolt that’s fully rusted in place, so scrub for 4-5 minutes until you’ve scraped off nearly all of the rust. Large hardware stores may sell wire brushes specifically designed for stripping rust.
Saturate the threads with a rust-penetrating liquid thread loosener. Once most of rust has been stripped away, douse both ends of the bolt with liquid thread loosener. Let the liquid soak into the metal and work its way beneath the head of the bolt for about 30 minutes. Effective brands of rust-penetrating lubricants include Liquid Wrench, PB Blaster, and Royal Purple Maxfilm. Do not use WD-40 for this. While it’s an effective lubricant, it’s not effective at penetrating through layers of rust.
Strike the head of the bolt 6-12 times with a hammer. Once the rust-penetrating thread loosener has loosened up the rusted bolt, hit it with a hammer to jar the bolt out of the position its stuck in. Blows from a hammer can also create micro-fractures throughout the bolt, making it easier to remove. Vary the position of your hammer blows so they’re not all in 1 place. Hit near all 6 sides of the stuck bolt at least once.
Unscrew the rusted bolt with a long-handled socket wrench. The wrench’s long handle will give you more torque than a typical short-handled wrench. Hold on the very end of the wrench and pull by exerting constant, steady pressure. With enough force, the bolt should loosen and unscrew. If you’re not sure of the size of the bolt, try 3-4 different sizes of socket on the bolt until you find 1 that fits best.
Destroying a Stuck Bolt
Purchase a screw extractor that matches the size of your bolt. Find a correctly-sized screw extractor that can remove your stuck bolt by measuring the diameter of the threaded portion of the bolt. Take this measurement to a hardware store and find a screw extractor that’s about ⁄7 inch (0.36 cm) narrower. If you have the bolt measurement, the sales staff can help you find a correctly sized extractor.
Drill out the core of the stuck bolt with a screw extractor.A screw extractor is a long, thin piece of threaded metal that screws into an ordinary power drill. Set the point of the extractor into the center of the bolt, and slowly squeeze the power drill’s trigger. Drive the screw extractor down through the shaft of the bolt, and let it unscrew the bolt from within. Although this will destroy the bolt, it should make it much easier to remove.
Remove the drilled bolt with a box wrench. If the screw extractor doesn’t remove the stuck bolt itself, pull the bolt out with a wrench. Set the end of a box wrench over the head of a drilled-out bolt and turn it counterclockwise to loosen the bolt. If the screw extractor shattered the bolt and pieces of the bolt are left inside the material that the bolt was screwed through, you may need to give the bolt head and nut a few blows with a hammer to remove them.
Cut the screw off with a reciprocating saw if nothing else works. If the screw extractor fails to pull out your screw—or if the screw is too rusted for the extractor to penetrate—your only other option is to cut the bolt off of whatever it’s attached to. Insert a hacksaw blade into the reciprocating saw, and press the blade against the shaft of the stuck bolt. Turn the saw on, and cut through the bolt and the shaft. Keep your fingers and hands clear of the blade when cutting through a stuck bolt.
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