Brushes that are worn out, or oil-soaked, should be replaced.

When replacing field coil brushes, crush worn out brush with pliers, taking care not to damage pigtail.

Sand the pigtail end with sandpaper to ensure good soldering.

Insert the pigtail into hole provided in the new brush and solder it. Make sure that the pigtail and excess solder do not come out onto the brush surface.

When replacing the ground brush, slide the brush from brush holder by prying retaining the spring back.