'51 Buick Hood Hinges

[buick8]

Guys, my '51 Special has a problem I can't resolve: the hood hinge-latch on the rear, passenger side, works fine, but when I open the hood from the driver's side and set it on the prop, the hood flexes as its weight rests on the prop, and the hood disengages from the rear latch. Note the latch is not opening; seems that the hood is not engaged enough in the latch, such that the slight flexure of the hood moves it enough to slip out fo the catch.
The hinges and latches seem to work fine. I have owned this car about 30 years, and it worked fine until about 3-4 years ago. I have a factory manual, and it doesn't offer anything that helps; the hinges are pretty straightforward, and I can't see what's wrong.

[chub chub]

Are you sure the hood is fully latching when you close it on the pass. side? Or when the hood is fully closed, can you lift it some (from the latch in question)?