I recently bought two old Wico pinball lifts missing the hydraulic cylinders. In the next few weeks I was going to have a friend fabricate new brackets and do the required welding to change over to the pneumatic cylinder mentioned above. I will also be replacing the old beat up casters with new ones. Still trying to figure out which ones I want to use that will hold up and work well on a variety of surfaces without leaving marks or wearing out too fast.
Pinside user MikeO posted about doing this upgrade in a thread from a few months ago.
http://pinside.com/pinball/forum/topic/wico-pinball-cart-red-ryder-shock-conversion
-- Shawn