All AirForce units used permanently sealed motors in their main collection unit. They require no lubrication or oiling. Routine maintenance for typical residential usage should include checking the motor brushes approximately every five years. While checking the motor brushes, make sure the center motor shaft is solid and has no play or wobble. If it does, the bearings are going out and the motor will need to be replaced. If the motor brushes are worn to 3/16 inch long, replace the motor brushes.
If the unit does not have any paper or cloth bag filtration, then a certain volume of debris may accumulate on the motor's internal fan blades. This is not easy to remove and any attempt to remove it has the high possibility of offsetting the balance of the fans. An imbalanced fan causes premature motor failure on the motor bearings.
Here are instructions for checking and replacing vacuum motor brushes. Motor brushes conduct electricity into the motor while touching the center shaft. Over time, they wear down. If they wear all the way down, they can damage the motor.
Click on the image above to understand how a vacuum motor works.
Please contact MD Central Vacuum at 1-800-997-2278 if you are experiencing any problems with your Airforce Central Vacuum.
The AirForce motor has two carbon brushes in each motor that wear down but can be replaced before they damage the motor. AirForce motor brushes should be checked every five years in typical residential applications and should be replaced if the 3/4 inch-long solid carbon "brush" is worn down to anywhere near 3/16 inch. Here are instructions for Checking and replacing vacuum motor brushes. Motor brushes conduct electricity into the motor while touching the center shaft. To find the replacement motor brush for your AirForce Central Vacuum, type the motor replacement number (not brand model number) in the search box and the motor brush will come up in the search result; instructions are on the motor brush page.
Know that the AirForce motor may go bad for other reasons, such as bad bearings or dust build-up in the motor (both are not repairable). If your motor brush doesn't show up under your original motor model number, replace the motor, not the motor brush.