Morris Minor Owners Club

I'm repairing the sills on my 4 door. The edge of the floor (before it turned into the lower sill) seems in reasonable condition. The lower sill had a bit of a bodge repair, with a new panel welded over an old one, but cutting right back to the edge of the floor got rid of both panels, and I've got some clean metal to weld to. I was planning on cutting the 'flange' (that extends into the floor) off the repair panel and welding the new panel "on the corner" like this (weld in red, repair panel green, old floor blue):



However, inspecting the seam between the old floor and the upper sill, there does seem to be some surface rust. It's hard to photo, as it's in the small gaps in between the two pieces of metal:



Would it be okay to chemically treat that rust somehow, or is it best to drill out the spot welds and replace that floor edge too?

I cannot see the images you have posted, maybe others can and will comment.
If it helps you, I have a couple of videos on you tube showing how I tackled the floors on my 1965 2 door.

Link here : https://www.youtube.com/channel/UCsbZsl ... Z08ArjvOjA

I'd really get stuck in with a twisted wire brush on an angle grinder all along that seam and see if the rust goes any further. I agree with your idea of cutting off the flange on the lower sill repair panel and welding on the edge to the floor. It was all one pressing originally when the car was built. I didnt do that on my traveller and regretted it. It's a test for the welding skills however but it sounds like you're pretty handy in that department