How To Check if Carbon Brushes Are Worn & Need Replacing?

There are many different working parts within your power tools such as switches or carbon brush caps and that can often make it difficult to identify which part of your power tool is causing the problem.

With so many working parts, it is inevitable that things will go wrong and whether that is through a fault or heavy use, it is important that you can identify where the problem lies. One area of your power tool that can cause problems is the carbon brushes and when the time comes to replace them, you need to know that they are causing your power tool problems.

What are Carbon brushes & Why are They Important?

Carbon brushes are a small but essential feature of all power tools (1). They conduct the electrical current between both the stationary and rotating wires inside motors. They handle a lot of energy, and so are designed to wear over time.

Once a carbon brush starts to wear down, you may notice performance issues with your power tool.

However, identifying when that time comes can prove difficult, but spotting the signs early can help you to get them replaced quickly while preventing further damage to your motor and your power tool, which takes us to the next step.

How long do carbon brushes last? Click here

How to Know if Your Carbon Brushes Need Replacing?

When your motor brushes are worn, you will notice the following signs:

1. Reduced performance: One of the first things you'll notice is the tool will stop performing as well. You may have to shake it to get it going, and it will likely not achieve the high RPMs it used to.

2. Burning smell: The next common symptom of a bad carbon brush is the smell of burning. This is a sign the brushes are completely worn, resulting in friction between parts.

3. Sparkings: While minimal sparking is common in power tools, frequent large sparks are not. This is a sign your carbon brushes are wearing out. You can monitor the sparks through the cooling vents on your tool, which should help you gauge if it's getting worse.

4. No Power/Inconsistent: The final sign your carbon brushes are wearing out is if the tool starts cutting out during use. This is a clear sign they have completely worn away.
   

Can you fix carbon brushes?

You can't fix a worn or damaged carbon brush, so all you can do is replace it with a new one, which is actually quite simple to do.

Need a new set of carbon brushes? Top Deals Online is a dedicated supplier, where you can search by Tool Model here, to help find the exact brush for your tool.

We stock brushes for popular models like the Titan TTB280DRH and the TITAN TTB278SDS.

Benefits of Maintaining Carbon Brushes

Your power tool might be something you use at home or it might be something that you use for your job on a daily basis, whatever it might be, you should consider actively maintaining your power tools. While it is acceptable to let your power tools show you that it is time to replace the carbon brushes, it is not always the right thing to do.

There is no need to check the tool on a daily basis but every now and again, it can help to take a look at the carbon brushes to make sure that they are looking good and fit for purpose.

You should not leave worn carbon brushes inside your power tool for too long as this can damage the armature which is a costly repair itself. Therefore, keep an eye out for the clear signs of underperforming power tools, bad smells and sparking as this will indicate that the carbon brushes need replacing.

Read more about maintaining power tools here.

How to Test If Carbon Brushes Need Replacing?

To test your carbon brushes, monitor themuntil they are worn down to around a quarter of an inch, as this is usually a good time to replace them.

If the brush displays signs of breakage, crumbling or burning then it should be replaced.

If there is any change in colour to the spring (such as rainbow patterns), this could indicate that there is a broken lead in the spring, and so should be replaced.

Also, if the spring has collapsed, then that will mean that the carbon brushes will also need replacing.

Guide: How to Change Carbon Brushes in Power Tools

What do Worn Carbon Brushes Look Like?

When a carbon brush reaches less than 50% of the total size of the carbon brush holder, it's worth considering replacing it. This is a rough guide as to how large the original brush was.

Here are some images below to illustrate what a worn carbon brush looks like: