From what I remember when I did my diff pinion oil seal, admittedly on an early 1500 but I dont think there much difference, that seal that you can see
is probably a leather seal held in a pressed mild steel case. I think that the leather wears out and also dries out if you dont use your car very
often.
I dont think that you will need the pressed steel holder again, so long as you are replacing the seal with a nice new modern one.
If thats the case you can either use a small chisel to collapse the pressed steel in on itself, and lever it out, or drill a couple of small holes in
the pressing, partly screw in a self tapper, and use that to lever the pressing out.
Malcolm

1975 1500