Bummer that the cylinders were destroyed.
FYI the part being referred to is the ‘gland’. I cant see the diagram but the other descriptions make it clear.
On my b8200 w/bf300 i had no real trouble getting the glands to move in a bit to remove the retaining ring. You do need to tap them usually with some kind of drift that isn’t going to damage the cylinder rod if you slip. For future reference, if you simply could not get the the gland to move in the conventional way, you COULD tilt the bucket down a bit below level, and then cut a piece of angle iron perhaps 1-1.5” on a side, to the length of cylinder rod that is exposed. Put a piece of cardboard or rag etc between the angle iron and the cylinde rod, lay the angle iron on the rod and strap to it (probably with hose clamps but really anything you come up with), and then remove the base end hose from the bucket cyls or at least loosen it until it is good and leaky.
Then bang the bucket into the ground with the loader arms. Should be that the angle iron will transfer the force from the cylinder rod onto the top of the gland and drive it in just a bit. Remove the retaining ring. Now the gland might be good and stuck in THAT direction but thats ok because you can push it out with the hydraulics.
Just reconnect the base end hose, unhook the cylinder rod from the bucket, and slowly push lever to extend bucket cylinder until it is fully extended. Once it is fully extended, any further hydraulic pressure will drive the whole gland/rod/piston assembly out of the cylinder. Just go slow so it doesn’t pop out too quickly/forcefully.
Now, it WILL dump a whole cylinder worth of fluid out if the cylinder is pointed down during this, so have a catch pan and a catch man. The man is for catching the rod so it doesnt bang into something on the way to the ground and put a nice ding in your shiny chrome.
If you’re working by yourself you could do something like get a pool noodle and cut a slit in it or some of that foam pipe insulation and just cut it to length and slip it around the rod. If the bucket will actually mechanically rotate further than the cylinder can extend you can just leave the rod end hooked to bucket (other cylinder must have rod unhooked though) and have bucket edge only an inch or so above ground so when the rod pops out it basically doesn’t go anywhere.
Anyway, that’s for next time. Good luck with your cylinder search.