Rear drum removal

I sense the brake pedal has more travel than 20K miles ago.

I checked the front pads and they appear to have little wear. I then attempted to remove the rear drum to check those shoes. Problem. The only opening is at the top front, a rubber insert, which when removed offer little detail.

Never in my time of working on vehicle have I not be able to remove the rear drums. These are very snug and do not move with light prying around the edges.

Your thoughts.