How to Remove a Stripped Bolt or Nut with Pliers

Removing a rounded bolt from your vehicle with a regular wrench or socket is not easy. But it is fairly manageable with the right pair of pliers if you do not have a bolt extractor socket. In this article, I share how I use pliers to remove the stubborn stripped bolts and nuts.

Stripping the head of a fastener can happen at any time during the removal or installation process. But how do you remove a stripped bolt or nut when you come across it in your project? Do you get a stripped bolt remover or call your mechanic who shows up with some fancy-looking pliers? Now, imagine your mechanic is out on vacation and you cannot find a rounded bolt extractor, What do you do? I go for pliers!

In this article, I share with you how to remove a rounded bolt off with pliers. But first, let us understand what is a stripped bolt or nut, what causes stripping, and how you can stop it.

What is a stripped bolt

rounded bolt
Rounded bolt

A stripped bolt or nut is one that has flattened or smoothed corners. Better said, it is a fastener with rounded edges.

When a bolt or nut has rounded corners, a socket or wrench cannot grip it properly to turn it. Sometimes if the edges are damaged so bad, the wrench only slips over the fastener without having any grip.

So, when you notice that your wrench or socket does not get a good grip on the fastener or spins around it without loosening or tightening, the fastener could be stripped. However, sometimes the wrench could be the problem. Therefore, it is important to visually inspect the bolt head or nut before concluding that it is stripped.

Why does a bolt get stripped?

There are many reasons why a bolt or nut can get rounded or stripped. They include:

Overtightening

Applying too much torque on a nut or bolt can exceed the fastener’s tensile strength. As a result, the wrench may snap off the bolt head or nut and cause the corners to flatten or smooth out.

Cross-threading

Cross-threading is when the threads of a bolt or nut do not mate properly with those of the threaded bolt hole or stud, respectively. It can occur when you apply a fastener at an angle and force it onto or into the mating surface. As a result, the excess torque you apply on a cross-threaded fastener may cause its head to yield and before you realize it, round off the corners.

A cross-threaded fastener does not turn as smoothly as a properly installed fastener. Also, it becomes harder to turn the fastener as it cuts across more threads.

Cross-threading can not only cause the nut or bolt head to get stripped but also the threads. In fact, the threads get marred first before the head. So, it is important to pay attention to how smoothly a fastener turns to avoid ruining it and the mating surface.

Aging or Corroding

Over time, fasteners age and become weak. They also corrode and rust if they are exposed to harsh conditions. For example, rust tends to build up quite easily on exhaust bolts because of their exposure to heat, water, and other oxidizing agents from the environment. It is even worse if you live in the salt-belt regions where corrosion is a bit of a problem on metal fasteners, especially on vehicles.

An old rusty or corroded fastener becomes soft and easily malleable. So when trying to get it out or tighten it down, you can easily strip it.

Using the wrong wrench size

If you use a bigger wrench or socket to break loose or tighten a nut or bolt you will strip its edges. You may also damage the corners of your wrench when the two metals slip over each other.

An adjustable wrench is another culprit of stripping bolts because it does not provide enough contact points. So avoid using it to tighten down or break loose fasteners.

Poor quality bolts and nuts

If you use poor-quality bolts and nuts, you will strip them at one point because they are not strong enough to withstand a lot of force.

Using air impact wrench to break loose siezed bolts

An air impact wrench is great for breaking loose a fastener because it applies continuous short bursts of intense force onto a fastener to break it loose. However, the impact wrench is only good for busting stubborn but not bolts. The reason is that bolts are delicate than nuts and require a bit more control over the force. Unfortunately, air impact wrenches do not give you much control over the torque and as such may strip your bolts.

How to avoid stripping bolts

If you want to stop stripping bolts and nuts, do the following simple things:

  1. Use the right socket or wrench for your bolt or nut. Not bigger or smaller!
  2. Don’t overtighten nuts and bolts. Use a torque wrench to apply the right amount of torque.
  3. Avoid cross-threading your fasteners. Always apply them upright, not at an angle!
  4. Install quality bolts that manufacturers recommend.
  5. Don’t use an air impact wrench to break loose stubborn bolt. Instead, try whacking it with a hammer and use ratchet wrench. You can also try a hand impact tool.
  6. Apply some penetrating oil on a stubborn nut or fastener and let it sit for some time before trying to remove the fastener.
  7. Replace old and rusty fasteners before they freeze up on you.

Although these tips will help you avoid stripping fasteners, it is good to always be ready to deal with the ones that get rounded anyway. One way to be ready is to have a proper set of pliers for removing stripped bolts and know how to use them. In the next sections, I will share with you two different types of pliers you can use to remove nuts and bolts with rounded heads.

Removing Stripped or Rounded Bolts and Nuts with pliers

Removing Stripped bolts and nuts with Water Pump Pliers

removing a stripped bolt with water pump pliers
Removing stripped bolt with Knipex cobras

Water pump pliers are a type of pliers for gripping round objects such as pipes and bolt fasteners. They have adjustable jaws that can adjust to different widths for different applications. Also, water pump pliers are available in different designs and sizes and from various brands. My favorite of them all is the Cobra from the Knipex Tools.

The Knipex Cobras have a unique offset V-jaw design that makes them useful not only for gripping pipes but also bolts and nuts. The teeth on the jaws are angled in different directions so that they can bite hard onto a rusty or rounded fastener. Furthermore, water pump pliers have long handles to provide more leverage.

Another unique feature of the Knipex cobra pliers is the self-locking mechanism. Though not as effective as that of locking pliers, the self-locking feature allows you to apply tension onto a fastener without necessarily squeezing the handles all the time. Also, as you apply more pressure onto a workpiece the harder the tool grips onto the workpiece.

Follow these steps to remove a rounded bolt or nut with water pump pliers.

Tools needed:

  • A pair of water pump pliers (I prefer the 10″)
  • Penetrating oil

Instructions

  1. Spray penetrating oil onto a rusty fastener. Penetrating fluid helps break down rust that is binding the fastener.
  2. Adjust the jaws of the water pump pliers to the size of your fastener.
  3. Squeeze the handles to clamp down onto the fastener. Ensure you get a tight grip.
  4. Turn the water pump pliers counterclockwise to break loose the rounded fastener. Here you will need some muscle. If you are using the Knipex Cobras you do not have to keep squeezing the handles. Just apply enough pressure onto the fastener and release the lower handle.
  5. Ratchet the fastener until it comes off completely.

If the water pump pliers do not take out the rounded bolt, you can try using a pair of locking pliers.

Removing Stripped Bolts with Locking Pliers

removing a stripped nut with locking pliers
Removing a stripped nut from a truck’s rear shocks with locking pliers

Locking pliers are a type of pliers that use a locking mechanism to lock down onto an object without letting go. They are also called Vise Grips after the company that invented and patented the locking mechanism.

Vise Grips pliers are available in different shapes and sizes for various applications. To use them to remove a stubborn bolt with a rusty head, follow these steps.

Tools and Supplies

  • Straight-jaw Locking pliers
  • WD40 or PB blaster penetrating fluid.

Steps

  1. Apply penetrating oil to the stuck rounded bolt or nut and let it soak for about 30 minutes. Penetrating oil breaks down rust, corrosion, and other grime on a siezed fastener to break it loose more easily.
  2. Grab your locking pliers. The straight jaw locking pliers are perfect for gripping the flat sides of bolt heads and nuts. Also, a longer pair of locking pliers provides more leverage than a shorter one. For automotive applications, a 9″ or 10″ locking pliers is perfect. If you are removing a bolt in deep areas, a needle nose locking pliers would be great.
  3. Grip the nut or bolt head with locking pliers. Simply adjust the jaws of the locking pliers to grip the stripped nut or bolt head tightly. Do this by turning the adjustment screw clockwise a few turns and squeeze the handles together until you get it tight onto the bolt or nut.
  4. Lock the pliers in position. Once you get the jaws of your locking pliers tight onto the fastener, squeeze the handles together to lock the pliers in place. You should hear a clicking sound.
  5. Turn the pliers counterclockwise to break loose the stuck rounded nut or bolt. Apply as much force as possible until the fastener budges. Continue turning until you get it all out.
  6. Open the locking pliers to release the fastener. Once the rounded bolt or nut is out, press the release lever against the adjacent handle to unlock the pliers in order to release the fastener.

Locking pliers are the best pliers for removing stuck rounded fasteners because once you lock them in place, you do not need to squeeze the handles anymore. This helps you to create as much torque as possible to break loose the damaged fastener. Also, the locking mechanism makes the job of removing stubborn nuts and bolts less fatiguing to your hand.