User’s Tip: Identifying and replacing worn motor brushes in Festool tools.

There are broadly two types of motors in Festool tools.

• BRUSH type. Festool powertools not designated as brushless have a brush based motor. Brush motors have a pair of carbon brushes conducting electricity via the rotating copper commutator bars on the armature shaft feeding the rotating armature windings.
• BRUSHLESS type (Festool designated EC for Electronic Commutator). These do not have brushes of any type.

Let’s discuss the brush type motor tools here.

Typical scenario. Your tool has quite a few hours of work under its belt and all of a sudden it just stops. It is probably not catastrophic as the motor brushes just need replacing. However, before assuming this, check the electrical connections and lead (safely wiggle them while the tool is switched on) and see if the fault is intermittent. If not, let’s go back to assuming the brushes might be the issue.

What are motor brushes? Brushes are a consumable part, they wear over time to avoid wearing out the more expensive and difficult to replace armature/commutator. The commutator does wear but more slowly, there is a finite number of times you can expect to replace brushes before the commutator is also worn out. Unless in industrial work situations, wearing out the commutator is unlikely and if it is time to do that potentially the rest of the tool may be nearing end of life.

Reviewing and replacing brushes.

If you suspect the brushes are the issue, it is usually as easy as opening the case and inspecting the brushes and replacing them if necessary. Before attempting any inspection or replacement ensure the tool is safe and all power is removed from the tool by unplugging it.

Please note: If you are not familiar with this type of work or are not suitably skilled, don’t open you tool and instead have your it fixed by a professional Festool repairer. If you need support with this please contact us on this page.

Steps:

1. Remove the relevant part of the casing. With Festool tools this is typically easy and clearly exposes the brushes for inspection. You might need a torx bit.

   Some older brush based cordless drills may have two straight slotted plastic plugs on either side of the body, just undo these to access the brushes.

2. Brushes are solid carbon blocks that make contact with commutator and have a wire coming out their end. Locate the brushes on either side of the copper commutator on the motor shaft. Take them out from their holder, usually by releasing a spring retainer or screw. There is a small braided or insulated wire connecting each brush to a spade connector. Disconnect this as well.
   
   
3. As the solid black carbon body wears down with use, at some point it would be too short to make good physical and electrical contact. Bad contact would cause electrical arcing and damage the copper commutator. To avoid this Festool uses auto-shutoff brushes. These brushes have embedded within the carbon block a small spring and insulated plug. When the carbon wears down to a point the carbon is well used but not fully depleted, the little plug is released and pushed by the spring towards the commutator. This lifts the remaining carbon off the commutator and stops the motor instantly. This avoids damage to the commutator caused by poor contact from worn brushes. Only one bush of the two needs to break contact and the motor can no longer run.

   Some tools have integrated carbon brushes and holder. In this case both are the holder and brush are replaced together. The brush is usually recessed in the holder the pops into place contacting the commutator when the holder is inserted.
   

4. If your inspection reveals the brushes are quite short in length or one of them has this protruding plug, then its time to replace both brushes.

   While the brushes are out, check the copper commutator bars for any signs of damage or uneven wear. If it looks concerning, then best have the tool professionally inspected or contact us for support.

5. Most tools have brushes specific to their motor, so installing the correct brushes is critical.

   You can locate the correct brushes using our Festool spare parts page. Use the diagrams reference by the tool B-Num or T-Num and identity the six digit brush code. You can order that part by inserting the six digit part code into the search box at the top of any Ideal Tools page.

6. Insert the new brushes into the holders, return any retaining clips or screws back in place, and finally connect the wires and spade connections. Replace any removed covers and your tool is ready for operation again.
   
   
7. Now test the tool operation. If both new brushes are correctly connected and seated the motor will start up as normal and all is good.

   New brushes can sometimes cause minor sparking and possibly a particular smell until the flat surface of the carbon block beds in and conforms to the radius of the commutator. This is normal. However, given any concerns, its best to have the tool professionally inspected.