I'm working with a vendor's hydraulic cylinder model supplied through Cardenas. The model is generated using a macro, and contains parts floating in space, which is fine, until I tried to make "extended" and "retracted" configurations... In order to save time, I fixed the components that never moved (ie. cylinder body, cap, head, tie rods, nuts, etc.), then made concentric mates for the clevice pins, piston, and rod. When inserted into the top level assembly, I made the cylinder assembly flexible so that the clevis's on either end could pivot. The problem I'm seeing is that once I make the sub assembly flexible, it seems to disregard that I've fixed a number of components, and scatters them in space as it sees fit. The weird part is that when I open the top level assembly (a strapping machine) and the cylinder solves strangly, I can fix it if I edit the cylinder and promptly finish editting. Does anyone have any idea why this happens and how to fix it?