Here’s a tricky job… In fact, that might be an understatement!
The replacement of the Quarterlight/Ventilator (the triangular hinged windows) seals is recognised by many Morris Minor owners as an absolute pig of a job – in this case I was replacing the top hinge which had sheered off at some point, leaving the window loose and able to fall out, and that requires the total removal of the ventilator window and the seal.
The hinge itself is attached to the top of the window frame by two screws on the top edge (Pictured below)
I’m not even going to try and explain how I completed this job – it was a lot of faffing about and involved a bit of head-scratching, and in the end I dismantled most of the passenger side window assembly, and it was still tricky. I found the worst part of the process was refitting the window once the hinges were in place – you can’t bend the window frame, but you can’t bend the ventilator! …Maybe there’s a trick to it, or maybe I’m missing something, but it’s not a task I wish to attempt again any time soon!
The old upper hinge, completely sheered. 
Trying to remove the hinge.
morrisminor.uk 