The part of the VW torsion bar that provides movement is a stack of 1 inch-ish by 1/8" ish flat bars [been a while, can't quite remember] stacked together to form a square "shaft" that slides through the tube and is held in the center by a female square welded into the tube. The arms have a female square that slides over the square shaft and locate in the end of the bar.
Some that I've seen have a 3 bolt cover over the arm where it slides into the tube that can be used to adjust the friction on the bar and slow down it's movement. Figuring out a way to bolt that arm down tight is all you need to do.
