63 Valiant disc brake swap kits?

If you have one good tight stud, thread a lug nut onto it so it's flush with the end of the stud. Tap on it with a hammer to remove. You just drive it out toward the backing plate. Then test fit the good stud in the holes where the loose studs were. If it fits tight, the hole is probably ok and you just need to get some new stock studs (probably RH ones as LH ones are getting a bit hard to find) Get matching lug nuts if necessary. Installing the studs is easy also. Just start the stud coming in from the back side. Use a socket or stack of washers over the stud and tightened a lug nut to draw the stud all the way in the axle shaft until the head of the stud meets the back side of the flange. Repeat on the rest of them. Done.