Those brass fittings are called "tube seats."
They are quite hard to find, other than at the rebuilders level.
I will look thru my computer files for you, and see if i come up with anything.
You remove them by getting a longer sheep metal screw, and screw it into the center of the tube seat.
Get out your small vice grip pliers, put it under the head of the screw, get out the hammer, and hammer up it out.
Easy peasy.
Yes, it does destroy the old tube seat, but in your case, it doesn't matter.
Brake Bleeder Screw Carlson H9446 | eBay
I had this number bookmarked, but can't remember if i ever purchased these or not.
