85 300TD Window Trim Leak
 

My 300TD has developed a leak at the bottom of the rear side window trim at the very back. I can reach up in the spare tire well and feel some flaking rust in the area. It doesn't feel like the drip rail trim area and the rust doesn't go all the way up to the window. It is maybe 3/4 inch wide and 1 inch long rusty area. How do I remove the bottom chrome trim piece in order to repair the rust. It's only maybe an inch long rust area but I want to get to it before it gets worse. Also is this a Bondo type repair or do I need to cut and weld in some metal?
Thanks
John

Can you take some pictures?

No such thing as a "Bondo repair". Bondo or any body fillers are for cosmetic purposes only. They will not stop the rust and usually will accelerate the corrosion process. They will absorb and hold moisture.

If the rust is surface only, you can treat and seal the rust using POR15 or its ilk.

If the rust has permeated the existing metal then it needs to be removed.

Either replace with metal or an epoxy. Many people have had good results using J-B Weld, POR15 Epoxy putty or their like.