rear window seal on 91 190E

I keep having water in the trunk. Apparently coming from the lower left an right ends of the rear window seals. Whats the procedure of changing this seal? Any experience?
They're not glued in, I understand. It leaks on my w123 and also on my w114, so a common issue I would believe.
My dealer told me, getting them 100% sealed on the w201 is even a very hard job for them.
Thanks for any input! Happy new year!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.