Is there a secret to easily work my sofa?

[Cali Native]

I 've had the sofa with bed extension for a couple years and haven't used it much preferring to leave it as a bed but recently I tried to pull it up into seating position and it is very difficult. We pull and push and it seems to not want to move at all like it's not even designed to convert and then after several attempts it seems to finally move for no apparent reason. I can't do it alone and so enlisted 2 young strong 17year olds last time and they have no idea what they did or didn't do to accomplish the conversion other than tugging, pushing, grunting, swearing and then voila success. I know it's hard to see behind the inverter but if anyone has an idea to help it would be greatly appreciated.

After further investigation and talking to the factory they relay that it looks like the springs are ok and that the spring ends sort of catch in the grommet when the bed is down. So not sure where to go on this one maybe leaving the bed down for a year or 2 stretched the springs?