Rumble Seat Help

[ricconhan]

Tinkering with my Roadster while waiting for other parts. My rumble seat "back" cushion isn't fastening to the lid correctly. My lid has 2 slots towards the top on either side and the back cushion has 2 tabs that slip down into these slots, there is nothing on the bottom of the cushion to attach to the lid and subsequently everytime I close the lid the bottom of the back cushion rubs on the seat cushion causing it to raise and the tabs come out of the slots, so when I open the lid next time the back cushion is laying face down on the seat cushion and I have to reattach it every time. What should be on the bottom to hold it in place. Pictures just for reference, not my car, just stolen off interweb.