I just used a length of 1/2" threaded rod, some flat washers, and a couple nuts, and that worked fine. The spring has pressure, but with the threaded rod I just remove the nuts from the clutch pack, then back off the 1/2" nut. After 5 or 6 inches the spring is fully expaned. It was easy. To line up the discs I held two 1/4" rods against the teeth of the discs.