All SilentMaster 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.
You have a couple of options when it comes time to replace the motor on your SilentMaster Central Vacuum. Contact a local dealer for service, or consider doing it yourself. Motors on the SilentMaster vacuum have a few fasteners and wires that need to be unattached, then reattached on the new motor. It should take less than one hour to change your motor(s). Here is a quick "how-to" change your motor:
- Use the SilentMaster Motor Replacement Parts Chart to find the right replacement motor for your SilentMaster model. When your new motor arrives, take some photos of your original motor so you remember how it was wired and secured.
- Turn off the circuit breaker or unplug the central vacuum unit.
- Access the motor by releasing the outer housing (usually a few screws around the perimeter). Remove the motor and unclip the motor wires from the components.
Note: Your new motor may not have the correct wire ends. If that is the case, we recommend cutting the wires from the old motor and wire nutting the new motor wire to the old motor wire. Using the original wire with the correct end to attach to the components makes your job a lot simpler and the connections safe and secure.
Note that a motor may have many numbers on it, but typically the complete motor number starts with "11" followed by 4 more numbers and maybe a dash with two more numbers (e.g. 115334-00). Years ago, they didn't put the complete part number on the motor.
For more information, see our detailed SilentMaster Motor Replacement Instructions.
The SilentMaster motor has two carbon brushes in each motor that wear down but can be replaced before they damage the motor. SilentMaster 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 SilentMaster 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 SilentMaster 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.