Reworked vent window, now roll up won't... roll up.

[Nomadicflyer]

ARGH. Spent the day rebuilding the vent window, replacing rollers on the window actuator, cleaning/lubing regulator, installing new felts, seals, wipers, welding the pivot post back on, welding captured nuts back in...

You'd think the old girl would be happy with the attention?

The drivers side roll up window won't roll up past the lower rear window track. Removed the rear window seal, no good, same same. Made sure the forward seal was set properly in the vent window frame. Yup. All the fasteners are in, nothing looks bent or broken. By all rights, this thing should rocket up and be smooth as a babies butt.

Need some ideas to try. Who's first?

1972 C20, same window parts that came out 2 years ago, at the beginning of the project.