If your angle grinder has lost power, is sparking more than usual, or has stopped running entirely, worn carbon brushes are the most likely cause — they’re the two small blocks that carry current to the spinning motor, and once they wear past their contact point, the motor stops getting a clean connection. The good news: replacing them takes about two minutes and costs almost nothing. Depending on your grinder, you’ll run into one of two designs below, and the process is slightly different for each.
Unplug it, or pull the battery, before opening anything
Always disconnect power before opening the housing or touching any internal components — both designs below involve hands near live electrical connections inside the tool.
What’s Inside!
How to Replace Carbon Brushes in an Angle Grinder — Video
Type 1 — External Cap Access
Some grinders have carbon brush caps visible on the outer body — no disassembly needed.
- Unscrew the cap on the side of the grinder body.
- Pull out the old brush.
- Insert the new brush in the same orientation as the old one. Direction matters — inserting it the wrong way causes premature wear.
- Screw the cap back on.
- Repeat on the other side.
That’s it. Your grinder is ready to use.
Type 2 — Housing Access
Other grinders require opening the housing to reach the brushes. It’s a few more steps, but still straightforward.
- Open the grinder housing.
- Locate the carbon brush holders inside.
- Unscrew the brush holder and disconnect any attached connectors.
- Remove the old brush — it’s usually held by a push lock, so a small screwdriver is enough to release it.
- Insert the new brush in the same orientation as the old one.
- Reconnect the connectors and reseat the holder.
- Repeat on the other side, then reassemble the housing.
How to know when brushes need replacing: most brushes have a wear line marked on them. If the brush has worn down past that line, replace it. Don’t wait until the grinder stops completely.
Recommended Carbon Brushes
Last update on 2026-09-27 / Affiliate links / Images from Amazon Product Advertising API
If you’re new to angle grinders, carbon brush replacement is just one part of keeping the tool running well. For everything else — discs, safety, cutting and grinding technique — the full beginner’s guide covers it all.
