Jockey Wheel Question

Hi,  New to caravanning this year and recently spent 2 weeks touring cornwall.  At a number of sites upon arriving at our pitch I unhooked and raised the jockey wheel to level the van.  On a few sites I needed to raise the wheel quite high to level off but found that when I rotated the handle to raise the wheel beyond a certain point I couldnt raise it anymore.  It was turning but slipping like it had run out of thread.  The only way I could resolve this was to ask for warden assistance to lift the caravan itself by hand so that I could physically drop the stem of the jocky wheel lower and then tighten it up quickly which gave me the additional height I required.  Do you think I have a problem with the jockey wheel itself or am I doing something wrong which is meaning I don't have much rotation available to raise the van to its desired height?