We just had a wobbly toilet in a 1960s-era house. I think I last got under it a decade or two ago to reseal it with wax. I figured the mounting screws just needed tightening this time. But no, they were tight. So what the #$%^&?
I removed the toilet and found that the closet flange, which the toilet was securely anchored to, had split off from the lead (as in, not steel) tube that was wedged into the 4-inch drain. That tube was about 6-inches long, so once securely wedged in the drain, the attached flange didn't need to be screwed to the floor to be secure. Well, as long as it was attached, which it was no longer.
So, OK, this is a heavy steel flange that had been somehow (soldered?) connected to this lead tube. The tube walls were pretty thick. About an eight of an inch. The flange just broke clean off from the tube.
Now unfortunately that left the lead tube stuck in the drain. I figured I could bend/pry it out, but it wouldn't budge. I ended up totally mangling the lead tube with a screwdriver, whacking it down the sides, and laboriously pulling chunks out. I'm guessing adhesive was used. Took more than an hour of mangling, but I finally got the full ID of my 4-inch pipe back. So I then installed a new PVC closet flange, and anchored that to the floor.
But really, a closet flange attached to a heavy lead pipe glued into the drain?? Has anyone seen a toilet mounted in that way? How might that pipe be more easily removed from the drain?