Since I got my vert about 10 years ago, I've had problems where there would be a couple of inch gap between the roof and the latches when the roof went too the closed position. It never took much effort to pull the roof down to latch it closed. The past year or so it started to take more effort, until tonight when the gap was about 3 inches and I couldn't get the roof to latch. I'm sure I screwed something up by not getting it looked at sooner. What could be the cause of the problem?