Try to find out who the manufacturer of the actuator is. Then do some snooping around here for parts:
http://www.championtrailers.comhttp://www.etrailer.comhttp://www.easternmarine.comI've bought parts from all of them rebuilding my 1994 Load Rite. All are pretty good. Champion Trailers has a lot of tech information and if you call them they will help with information if they are not too busy at the time you call.
I learned a lot putting in a new axle, springs, complete brake system, new roller bars, etc.
Even learned how to make drum brakes keep working in salt water....