You did not mention if you want any kind of feedback control? I assume there is not at present with the HYD's?
What you need to be mindful of is whether it is possible to stall the motor at the end of the stroke, with hydraulics it does not matter.
I would look at either a DC or BLDC motor controlled by a A-M-C drive, both these are available on ebay.
The drive would give you some variable control and also has O.T. limit inputs for each stroke end.
Another alternative is a DC motor or Treadmill motor with a simple KB DC SCR drive, again you have some variable control.
You can get sophisticated VFD drives using encoder feedback that will perform close to servo performance, but IMO the former solution would be cheaper and more flexible.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.