If your motor brushes are sparking, it may be a sign that they need replacing.
If after inspecting your carbon brushes you notice signs of breaking, crumbling or burning; then it's definitely recommended to replace the immediately.
Check to see if there is a loose carbon brush cap, or any excessive dirt or bits in the mechanisms that could stop teh brushes from working correctly.
If there is a discolouring on the spring such as a raindbow pattern, then it could be a sign of broken lead in the spring, which indicates a replacement is needed.
If the spring has collapsed completely, then you definitely need a new brush.
You should leave worn brushes in a tool for very long, as they can damage the armature which is very expensive to fix.
To monitor the sparking from your tool, you can check the air vents when in use, and this helps you to gauge how much the sparking has changed over time.
Top Deals Online is a UK based supplier of replacement carbon brushes, where you can search for the exact brush to fit your tool by model and make. Click here to learn more.