Hi guys, ok progress so far on this "learning issue" is that I've experienced this button's two states today: completely frozen feeling, and depressable although perhaps not as far as needed.
The posters suggesting some kind of jiggling tapping etc were right, although what I did to get it out of the frozen state was accidental. I pulled on the flail blades to rotate the drum to try to turn the shaft enough so the button was where I could see it better. Oddly I could see something inside the pto shaft rotating but the pto on the tractor didn't turn much if at all???? In any case it got the button out of the frozen state. Good thing, I couldn't find a way of getting a hammer or other metal object in under the cover to hit it very well. So it is out of the frozen state, and has had the socks sprayed off it with silicon lube.
When the tractor is off and the pto is disengaged, should I be able to turn the pto shaft with the implement? In both directions? I thought I remembered being able to turn it by hand before I attached this thing the first time but the dealer tech was patiently showing me (blessings on him) and I might have missed something. I have a 3560HST. There is a yellow knob that you push down and turn to engage the pto, but I don't know if it works when the engine is off.
So now it is on to the spring thing. I didn't want to try too hard to remove it all the way tonight in case I couldn't get it back on
I am not done mowing. On my list of things to try to depress that button if my thumb is still inadequate, and hold it long enough to move the collar things is a C clamp. I had imagined a fancy plier gadget, maybe with two jaws on one side and one opposite, but I don't know where I'd find one.
Bmblank, do you know if you have to replace the whole pto shaft to use those collar connectors?
Thanks everyone!