I recently obtained a Beogram 4002 DC motor from France that needed some repair. My typical first step is to rejuvenate the oil-impregnated brass bearings by submerging them in oil. This process is usually successful in restoring motor function. This image displays the motor in its initial condition upon arrival:

To access the bearings, I took the motor apart:

The bearings are the two small ring-shaped components on the black surface.

I submerged the bearings in motor oil and created a vacuum. The appearance of bubbles confirmed that air was being pulled out of the bearings, creating space for fresh oil:

After a day, the bubbling ceased, and I reassembled the motor. I used my custom-made 3D printed tools to correctly position the upper bearing:

Here, both bearings are shown back in their proper positions:

Next, I conducted a 24-hour RPM stability test using my specialized Beolover RPM device. This tool is vital for identifying any fluctuations in RPM as it records the RPM over a period of time:

The Beolover RPM device is accessible to other enthusiasts. You can reach me through the contact information provided on my website. The following graph presents the RPM readings collected over a 24-hour period:

These outcomes are optimal. The motor is now fully restored and ready for use.