Welcome!! I just sold my 959, a machine I'm fond of but never used. It was loud but very strong and responsive; it had no problem with multiple layers of Levi's denim. And I like its Art Deco design.
When I bought mine, it had a lot of old oil varnish on the inside and out, so I applied kerosene to a toothbrush and most of it melted away. After that (and clear sewing machine oil), it ran more smoothly.
If the "rubber" on the pulley has an indent from years of non-use, you can sand or cut the rubber to the level of the indent to avoid the rough bumping each time the indentation contacts the wheel. FYI, make sure you look at the manual, as it has a picture of the angle and depth of the pulley-wheel contact.