[Walt Fricke]

It is at least 36mm, because I have a bar that big in mine, and it is the largest which will fit. However, for the main tube you can just measure its OD under the car, and subtract a bit for wall thickness.

Let's hope just one bar is broken. That way (this does have the 915 transmission? It's an 84 or 5?) you (or your mechanic) can remove the good bar on the other side, and use a long rod to punch out the splined stub on the broken side. Once that is loose in the torsion tube, a magnet on a rod will easily pull the broken part out.

If both are broken, getting the stubs out could be a significant issue. It is possible to cut out the torsion tube where it is exposed, and weld a replacement in. But that's major surgery.

Maybe someone has a better idea for a two bars broken situation.