This is probably the simplest hydrostatic idea I have ever seen or come up with  . So if the flaw is obvious please enlighten me. Like mentioned in the topic, this does not use any gravity so imagine this being in gravity less space to stop the confusion. Although the wheel should be of course pinned to something in order to rotate.

To summarize the idea. You have a tube with a fluid and two plungers,pistons... ,w/e you want to call them, on both sides. so if you pull on one, the other will go along just like illustrated where the bottom plunger is pulled. Now you do something clever (or stupid  ) and pull a little offset to the middle of the plunger. Now the reaction depends on how your tube is pinned to the wheel. If it's pinned like illustrated the tube will not have a tendency to rotate and just pull the other side BUUUUUUUUUT when this other side is attached to a wheel all hell breaks lose. Because now this force can produce a net torque on the wheel and rotate it while the force you pulled with was radially and does not rotate anything! Again this is stupidly simple so I'll keep digging.

That's pretty much it. Your feedback is appreciated.