Ok...this may not be a direct reason why the jacks bind, but I do agree that they will bind up if they flex to far...have you seen my post on supporting the front jacks???....take a quick look at this....this is a mod I did to mine.
http://www.motorhomemagazine.com/boards/Index.cfm/fuseaction/thread/tid/24021668/gotomsg/24025277.cfm#24025277 Now that I stiffened up the front,I have less binding and the camper doesn't (walk) along and shift so bad. It would work even if you didn't have the swing out brackets. I have said this before and I'll say it again....A major flaw with the Happijacks is that you can run them in pairs side to side but not in pairs front to back.