Picture #25: Here the brushes (in good health) and many carbon particules. Picture #26: Here the stator and rotor. Picture #27: Clean the brushes assembly. You can use an electrical cleaner. Picture #28: Spray an electrical cleaner in the motor assembly (do it over a container). I couldn't remove the rotor (there was some kind of spring). Note the end of the shaft. Picture #29: Note the carbon deposit on the rotor. Picture #30: Using a Dremel with a wire mesh, I have cleaned the contact area. I took a nylon (kind of) brush first but it did nothing. Picture #31: Re-assemble the motor. Slide the brushes assembly down the shaft but it will be stopped by the brushes themselves. Picture #32: Take a small screwdriver and push away the brushes and slide down the assembly. You won't be able to lock the brushes assembly to the motor because the small clips will be broken. Don't worry, once in place in the wiper assembly, it won't move or open. Also, I don't know if we have to put some kind of oil or grease but I didn't.