How To Replace Worn-Out Carbon Brushes
DIY Projects,  Hardware and Tools

How To Replace Worn-Out Carbon Brushes

Electric motors are found in many common power tools. They’re what makes appliances move and work. However, the carbon brushes that conduct electricity to the spinning armature inside the motor will wear out over time. When this happens, it’s time to replace worn-out carbon brushes.

What Are Carbon Brushes?

Carbon brushes are parts of an electric motor that need regular replacement. The electric motor has two main parts, the stator, and the armature. The rotor is the moving part that contains electromagnets, while the stator is the stationary part that contains permanent magnets. Carbon brushes make contact with the commutator (a part of the armature that reverses the current flow in the coils at each half-turn).

The carbon brushes’ job is to provide an electrical connection between the armature and the power source. It uses a spring-loaded mechanism to press the carbon brushes against the commutator. As the carbon brushes wear out, they’ll become less effective at conducting electricity. It’ll cause the power tool to run slower or not at all. Sometimes, it can also cause the tool to make a loud buzzing noise.

How To Tell If Carbon Brushes Need Replacing

Power tools are an essential part of any home improvement arsenal. But, over time, even the best power tools will need maintenance to keep them running smoothly. One of the most common issues is worn-out carbon brushes.

There are a few signs to tell if your carbon brushes need replacing. These include the following:

  • The power tool starts making strange noises. Banging noise is a common sign that carbon brushes are beginning to wear out. A deformed carbon brush might also get stuck in the slots of the commutator, causing a loud banging noise every time the armature spins around. It can also bounce off the commutator, causing a more consistent thumping noise.
  • The power tool starts losing power or running less smoothly than usual. It can be due to a loss of contact between the carbon brush and the commutator. The tool will be less efficient when the brushes can no longer bridge electricity between the armature and the power source.
  • A burning smell from the power tool might indicate that you need to replace the carbon brushes. When the carbon brushes begin to wear out, they’ll produce sparks, which can cause the armature to overheat and start to smoke.

If you notice these signs, it’s time to replace your carbon brushes.

How To Replace Carbon Brushes

You’ll need to prepare the work area and gather the necessary tools to replace carbon brushes.

Tools needed:

  • Screwdriver: You’ll likely need to remove some screws to access the carbon brushes. There are many types of screwdrivers, so make sure to get the right one for the job.
  • Carbon brush replacement kit: This will include the new carbon brushes and any other parts needed for the replacement.
  • Long Nose Pliers: You might need to use pliers to remove the old carbon brushes from their holders. A regular pair of pliers might work, but long nose pliers will give you a better grip.

After preparing the tools you need, follow these steps to replace your carbon brushes:

1. Unplug the appliance from the power source and allow it to cool down. Remember that the armature can get very hot, so be careful not to touch it. Unplugging the appliance will also help prevent accidental electrocutions. Safety should always be your top priority when working with electricity.

2. Remove the tools’ housing. This will give you access to the armature. On most tools, the housing is held in place by screws, which you can’t remove with your fingers. Use a screwdriver to loosen the screws, and then remove the housing.

3. Locate the carbon brushes. They’re usually easy to spot because they’re the main contact points between the armature and the power source.

4. Use long nose pliers to remove the old carbon brushes. Gently pull them out of their slots. If they’re stuck, wiggle them back and forth until they come loose.

5. Inspect the armature for any damage the old brushes might’ve caused. If there’s damage, it’s best to replace the armature.

6. Install the new carbon brushes into their slots in the armature. Make sure they’re seated properly and not loose.

7. Reassemble the power tool by putting the housing back on and screwing it in place.

8. Plug the power tool back in and test it to ensure it’s working properly.

Replacing carbon brushes is a relatively simple task that anyone can do at home. By replacing them yourself, you can save money and extend the life of your power tool.


If your power tool is starting to make strange noises, smell like it’s burning, or is losing power, it’s time to replace the carbon brushes. Unplug the appliance from the power source and allow it to cool down before beginning the replacement process. After you remove the old carbon brushes, inspect the armature for damage. If there’s damage, it’s best to replace the armature. Install the new carbon brushes and reassemble the power tool. Test it to make sure it’s working properly before using it again.

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