Sorry about post #5, for some odd reason it ended opp in this thread. Wrong post entirely
Don't hesitate to take the tension assembly with stud out. You probably don't have to take the entire stud - bolt thing out, but inspect the release pin from behind, does it run freely in there. It should be clean and not oiled. Some times dust, grime or something get stuck in odd places. Let the release pin drop out, and poke something in there to check if it's clean and unclogged. Machines in fold away cabinets are very prone to have oil seeping in every where, and with time it gets sticky.