Tool Maintenance: Changing the Brushes on a 3″ Random Orbital Sander

The Griot’s 3″ random orbital sander is a Delta Kits’ top seller and a favorite among headlight restoration professionals worldwide. Not only is the tool easy to use, it is also extremely durable. In fact, if used occasionally for sanding and polishing tasks, the Griot’s tool will often last a lifetime without any required maintenance.
When used regularly for extended periods of time, however, all electric power tools require regular maintenance for optimum performance. Headlight restoration is likely one of the most demanding tasks for a 3″ random orbital sander. So, Delta Kits includes an extra set of motor brushes with every Griot’s tool we sell. This is the number one reason for power tool failure, and it is easy to fix yourself.

What is a motor brush?

A motor brush is typically made of carbon block (graphite). It attaches to a small spring that holds it against the commutator bars on the armature to create electrical resistance. For the motor to function properly, it is important that the brushes are in good condition. Brushes do wear out over time. How long is dependent on how you are using the tool.

How do you know when it is time to replace your motor brushes?

If you see more sparks than usual through the motor vents or if the tool begins to smell like burning plastic, it is likely time to replace the brushes. If the tool begins to slow down, run inconsistently, or if you experience any other performance issues, it is likely time to change the brushes.

Generally speaking, if the brushes are worn to a length of ¼” or less, they need replacing. Additionally, if there are any signs of breakage, crumbling or burning, replace immediately. A discolored or collapsed spring also indicates the brushes should be replaced. Failure to replace worn brushes can cause damage to the armature, requiring much more costly repairs.

If you do have to replace the brushes on your 3″ Griot’s random orbital tool, we recommend ordering an extra set to have on hand to eliminate any downtime, part number 58000.

The good news is brushes are inexpensive and replacing them on most power tools is relatively simple. This short video from Delta Kits shows you how!

58020 120V Professional 3″ Random Orbit Sander

58010 240V Professional 3″ Random Orbit Sander

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