I'm wondering if the other option is to shim the top of the channels inwards?
its a PITA!
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Yeah,that might work.Try it and let us know. Good idea! It may pack it off the weatherstripping.
I had a plastic track guide break in half,jamming the window 1/2 up! It was bad!! That was my first experience. It's tough,you have to just work at it.I had more luck with just picking one side and keeping at it. Try an adjustment,then work them up/down. Over,and over,and over,and over.Now I got new(er) 1/4 glass I gotta' put in.