electric window on 67 dodge charger

[nchrome]

Okay guys l'm working on a 67 Charger power windows  And am having trouble with the right rear window. The spring is on rite but when l roll it down to the stop at a certain piont its like it is over center kinda and to make it go up you have to grab the bottom of the window carrier and kinda pull it forward and up then after it gets started then it will go up on its own. What am l missing here? Still trying to get it centered on the window channel opening again struggling with it.