Grandville86

Hi, Recently, my sofa/bed in my 86 Grandville will not release and I can not convert it into bed - stays in the sofa style. I have tried everything from rocking back & forth - to pushing downward on one side - still will not release. Anyone experiencing this problem before. I would like to resolve if, possible or do I need to pull the entire frame with sofa/bed attached. Seem heavy & difficult to pull out of motorhome - tight space. Thanx Debra