: Is the tool available?

: Will there be any more surprises?

Check your local plumbing supply store. If you are comfortable with the knowledge and skills necessary to rebuild/reseat an obsolete old piece of junk like that jameco, you're probably better off buying and installing a more modern tub/shower valve, though. the new ceramic disc type valves will never need servicing/replacing and are resistant to mineral build up from hard water and other problems you'll be fighting again and again with that old valve.