Thanks for the response NewZed.
My Z is a 78 2+2. The handles and rods operate fine, it's the lock release that doesn't operate properly thus not allow the latching mechanism to release and open the door. When unlocking the mechanism, the lock doesn't seem to be fully disengaged and when operating any handle, it felt jammed and hard.
After my friend blew the spring that helps the latch release (idiot), I applied heat to the area where the lock mechanism is (hard white nylon?) and it now moves, it now allows the handles to operate "freely" when unlocked, but still doesn't release the latching mechanism to open the door.
I'm having a hard time loading pics, but I'll try tomorrow and also a video.
Thanks again.