out-door faucet leaking. can't remove valve

[Decades]

outdoor faucet is leaking out the handle and faucet opening. Want to replace both washers in the valve. Took off the handle and bonnet/packing nut. Go to unscrew the valve and can't get it out. It unscrews all the way till it gets to the opening. The opening in the faucet doesn't seem big enough for it to fit through. What am I not seeing here?

 

[Decades]

turns out the culprit was a non brass thin washer that had rusted and embedded itself in the opening. I put the handle back on sprayed with wd 40. With a bit of pressure was able to unscrew it and get the valve stem assembly out. Next issue tried to unscrew the bolt at the bottom of assembly to replace that washer, Bolt head is disintegrating, unfortunately was not brass. Is it possible to replace this entire assembly? Am planning to use packing string for the bonnet washer as can't find this old odd, beveled washer.

 

[PJB12]

For the stuck screw, try boiling the stem for a few minutes. If you don't mind the smell, boiling it in white vinegar is even better.
Can you get small locking pliers (such as Vise Grips) on the screw for a very good grip on it? It may help.

If you're so inclined, it's possible to drill the screw out and re-tap the hole.

A real, old-timey hardware will certainly have the packing washer. They probably will have a matching stem, too.
Home Center? Skip the trip. A plumbing wholesaler may or may not have the washer individually. You might have to buy a kit.

Old fashioned packing string with graphite is my favorite, but that's just a personal opinion.

Best of Luck With It! You'll get it fixed!
Paul