Join Date: Dec 2000
Location: Dallas, Texas, USA
Had similar problem on my convertible. Yes, the plastic round rollers goes into the channel on the window guide. On mine, the lower adjustment screw that holds in the guide was out of alignment which, over time, was pulling the plastic roller out of groove. Bought new rollers for the window but had to grind them down a little in order to fit in the channel. Now it works fine.
The 1968 Service Manual has the details on this.
68 Camaro Convertible, 350SB,5spd,9"