Jim,
They are bike cables, usually Shimano....first one I have ever heard break... had to have one break eventually. Very easy to replace!
Duffer. make sure all connections are soldered and heat shrunk! The Motor/plunger should be basically water tight. Also you should have a fiberglass shield that covers them from debris from the wheel??? You can also add wheel grease to the plunger which works in more ways than one!
Jim-Terry does have the right ones!