Brush replacement is described on Page 12 of the manual as follows: (to download a copy go to


and download the HD77 and HD77M manual at the bottom of the page).


The brushes and commutator in your tool have been engineered for many hours of dependable service. to maintain peak efficiency of the motor, we recommend every two to six months the brushes be examined.

The brushes should be free from dust and dirt. Brushes should be replaced when they have worn down to 3/16″ in length. The brushes should slide freely in and out of the holders without sticking.

To check brushes: Disconnect plug from power source. Unscrew the brush caps on the motor housing and lift out the brushes; note which way they face, so that the brushes can be returned to their original position. Clean the brush holder openings with compressed air or a clean cloth and replace the brushes and caps.

Only genuine Skil replacement brushes specially designed for your tool should be used.


After about 300-400 hours of operation, or at

every second brush change, the bearings should be replaced at Skil Factory Service Center or Authorized Skil Service Station. Bearings which become noisy (due to heavy load or very abrasive material cutting) should be replaced at once to avoid overheating or motor failure.