How to Change Carbon Brushes in a Central Vacuum Motor

Small motors that power central vacuum units depend upon interior carbon brushes for their operation. After extensive use, the brushes become worn out and need replacing. When the brushes fail, they can also cause a whole engine replacement. Checking and changing the carbon brushes every few years is good preventive maintenance.

  1. Detach the cover from the vacuum unit to access the motor.

  2. Remove the covering for the motor. Some motor covers pop off while others requires removing screws.

  3. Locate the motor brushes either behind the cooling fan cover or behind the metal cover over the armature. Remove either cover and the brushes are easily visible.

  4. Unscrew the screws or the clip that hold the brushes in place and pull the brush out. Take note of the proper angle of the brush as it comes out so that the new brush will be put in the correct way.

  5. Measure the brush carbon to see if it is 1/2 inch or shorter. If it is, the assembly should be replaced. However, if the armature has pits or its bearing is loose the entire motor is no longer functional and must be replaced.

  6. Purchase matching carbon brush units from a supplier. Tell them the make and model number of the motor to ensure you have the correct part.

  7. Remove the flag terminal if one is attached to the new brush by clipping it off.

  8. Slide the new brush into place taking care that the angle is correct and that the spring is properly seated.

  9. Reconnect the clip holder or screws and put the motor cover back on.

  10. Test the motor to see if it works properly. If worn motor brushes were the only problem, the motor should start and run correctly.