What is the proper way to fix rusted out body mounts in the trunk pan? Is it just a matter of welding in patches? Or is it more involved than that? Not planning on a frame off restoration-just interested in a correct repair. This would have to be farmed out, so approximately how expensive would this be?
been there done that. Typically in the trunk area the gas tank will have to be removed, possible the rear bumper too. the part of the floor over the mount will need to be cut out and if the mount isn't too roached out ,a new piece of steel can be welded in from the top and drilled to accept a mount. unfortunately usually the frame is also thin and or blown through too and will need repair which can be tricky but not impossible with the body in place. Assuming its not too bad and your going for function and not show quality, not counting disassembly time required, the repair could be done by a skilled fabricator/welder in a couple hrs per mount. Again speaking from experience, its seldomjust one mount and the frame is often involved and the body is often in the way. the good news is that steel is fairly easy to work with the right tools.
Get a new trunk floor that comes with the mounts. If one is bad like he said the others can’t be long for this world.
There is another thread you can search for that shows how to repair a body mount frame . I attached photos showing how . DL