Reworking pop out windows

[alg]

Picture # 1 is the original window off my 71 Demon. Note in #1 top right (a) there is a sizable gap. This has been this way for as long as I can remember. At bottom rt (b), that rubber is extremely brittle. The remainder of this rubber is stiff, but probably serviceable. Is this rubber available anywhere? Failing this, any suggestions to fix the gap in this window?
Thanks guys. This car is nearly finished!

 

[dusterglenn]

This is something I need to deal with as well.

 

[Treblig]

I would get my windshield installation buddy. He carries tubes of urethane, you know, the stuff they use to install windshields. Anytime I need to fill a gap like that I just call him and he shoots enough in there to fill the gap. Once the urethane sets up you can wet your finger and mold it to some degree. You can buy a tube of urethane also but the rest of the tube will probably end up going bad unless you use it. You can also use black silicone but silicone is corrosive to metal and will make it rust before too long. Urethane is non corrosive.

Treblig

 

[76orangewagon]

I rebuilt my Quarter windows back in 2013 I was able to buy the rubber seals and the locking felt strips online. They fully disassemble once you drill out the long rivet that holds it all together. Search Duster Quarter window seals and pick your favorite vendor...there about $100.