The sliding door rails are covered by a metal cover, with the track attaching to a fastening strip at the top.
If this fixing strip is rusted, it's advisable to remove it, after which you can remove the rust from the metal behind it.
To do this, drill out the spot-welds with a spot-welding bit and fit a new strip by welding the holes in the strip. In this way, you reproduce the spot welds. If you do it properly, you won't be able to see afterwards that the band has been replaced.
Useful information from Paruzzi magazine and from our YouTube channel :
Look for more technical articles on the page Paruzzi Magazine