Hi,
Just a though: The reason the door is sagging is because the hinges are bending slightly with the weight, right? If this is the case, would I not be able to replace the hinge with its counterpart? So, replace the lower left with the upper right, and replace the upper right with the lower left. Reverse the sag? Is this possible? Or would it not work? If so I'll just buy the hinges.
Thanks,
Cameron