I feel like a butthole because heaters seem to start many threads...

... But I can't figure this out. Let's see if anybody can guide me a bit... Pretty please.

I must be doing something wrong or simply can't find the Damn bolt that connects these guys. Car is a 70 Dart with factory ac. I just ordered the seal kit from dmt and thought I'd get a head start by getting the boxes out and pulled apart... And then came the problem. I got the j hook and fire wall nuts. Hoses are detached and it looks good to go... The right side of the box moves freely, but it seems it is stuck and pivoting in the upper left side of the heater box where it connects to the ac part. Should I try to pull it as a whole? I have the manual and it doesn't seem to say anything about the ac cars... Only mentions the heater box individually. Any help would be greatly appreciated.