I am rebuilding a 1972 1800 E. The sills have been replaced a couple of times so I am unsure of how to properly secure the front and rear fenders where they overlap the outer sill. I have done research and comments vary from braze, weld, to just use seam sealer on the vertical seam. I assume this seam also exists on the rear fender to sill joint on a 122. Does anyone know how these seams were fabricated in the factory and the best approach for replacement. I would like to leave the seam visible. Thanks.

When I've done this, I just plug weld the fenders to the sills and leave the seam exposed as it should be. Then seam seal the seam and job done.

Thanks for the feedback. Plug welds was the method I used in the past and I intend to use at this point. It would be a hard place to spot weld in the factory. They may have brazed the seam since 1800s had brazing on top of the sill where it transitioned into the door post. Some MG posts indicate just seam sealer in the vertical portion on the joint.