Can you feel any resistance when you push on the clutch pedal..?? I had a 310B, and the clutch pedal worked very easy, so it's kind of hard to tell, but you can feel some resistance when you come up against the pressure plate to release the clutch. My 310B also had the metallic button type clutch, and would guess it would nearly be impossible for it to be stuck to the flywheel, whereas a fiber type very well could get stuck, if it got hot enough, or has been setting for a good while, and rusted to the face of the flywheel.
If you can feel some resistance, I'd suggest starting in neutral, and getting the hoe, and front bucket in transport position. Shut it off, then see if it will start in low, first gear. Drive it around with the clutch pedal depressed, riding/stabbing the brakes pretty good, and see if that will break it loose. If the brakes on it are like most of that model and era, they won't be the best either due to oil soaked brake disc's, due to a leaking bull pinion shaft seal. There is a small inspection port, approx. 1" - 1-1/2" in diameter on the right side of the bell housing part of the torque tube. It should have a snap in plug. You could spray some penetrant in through that hole towards the clutch disc/flywheel, to help break it loose.
Another problem could be, that the bolt holding the clutch release yoke has broken, or came loose. It is only a 3/8" X 2-1/2" bolt. If you have a very bright flashlight, and maybe later in the evening, like near dark, or have it in a dark building, you may be able to visually inspect, to see if the bolt is still intact.
There is one other thing that comes to mind, but in my case, it would not let the clutch fully release. If the inspection plug is missing from the torque tube, could be small varmints have packed the bellhousing full of debris. Ground squirrels had packed the bellhousing with nuts, string, and anything else they could get through that hole to make a nest. If they would get enough in there, it may cause the clutch release rod to flex enough, to not activate the release fork fully. If I remember correctly, that rod is rather flimsy. Big enough for what it was designed for, but not if it's trying to compress a lot of "stuff" that may happen to be packed in there.
If either the bolt is broke/loose, or is full of debris, then you'll need to remove the hoe & loader, and split the tractor to get it out. NOT a fun job... I pulled a 10 qt. bucket full of debris out of mine.
I would do a visual inspection first. Hopefully the snap in plug is still there, and it's just that the fiber type clutch disc is stuck to the flywheel.
Here is an exploded view of the clutch housing assy. to give you an idea of what it looks like inside.
Official Case IH Online Parts Store and Case IH Catalog for Best Parts Search and Best Parts Look Up. Case IH Parts for Case IH Tractors, Case IH Combines, Case IH Tractors, Case IH Manuals, Case IH Parts