Bigtonka's experience is interesting. It must be all about the weight.
I've towed a variety of vehicles with a tow bar. Not my favorite way to tow, I would prefer a dolly, or a chain with another driver, if I couldn't get both axles on a trailer or flatbed.
Anyway a couple of them were without engines or transmissions and they still pulled just fine. The steering was always complete, don't think it would work without it.
I guess if there is no weight on the front at all the caster could make the wheels flop over.
