To help with with the replacement in the future get some good penetrating break free sparay and spray the pivet point where the trailing arms meat the frame where the shims are. mine where frozen and had to be cut out.

Good luck and keeep us posted on any progress. I will likely be doing same on my 76 and will share what I find out along the way. It's kind of like two old gals having hip replacements, with therapy and plenty of cold beverages they will dance again.