For the third time in four years, the hinges failed on my KitchenAid wall oven. The appliance is out of warranty and KitchenAid does not consider this to be worthy of any recall. I was tired of paying the appliance repairman to change out the hinges, so I ordered the part online. Appliance Parts Pros is an awesome site for identifying the part you need, and they deliver quickly. Note that you probably need TWO hinges--they do not come as a set--and KitchenAid likes to make their model numbers indecipherable (GBS looks like 685).
I found the KitchenAid Allen wrenches to insert into the hinges with the door open, but these ended up getting stuck. (This misstep, honestly, was the only challenge.) Instead you should use the tiny silver hinge pins, which you might have from purchase or can order. The pins freeze the hinge mechanism so you can lift the door out. Place it on a towel on the counter. Remove 8 screws around the perimeter of the door including a bottom clip, and pull apart the layers to get to the hinges. Take the opportunity to clean all the parts if you want; be careful not to drop any screws inside the door. Align the new hinges, and reattach all screws. Do the perimeter first, ending with the ones that grab the actual hinge. You can gently twist/rock the foot of the hinge to line up the holes. Hook the hinges back into the face frame, open the door a bit, and remove those little pins. Save them for next time because my hinges failed without any misuse--I don't rest pans on the door, I don't slam the door open.