I used two springs from a battery case from a junk children's toy. These were bolted to the left and right of the tank door lock. On the opposite side, on the inner surface of the door, I put (with double sided tape) two soft rubber pads for a better fit.
It works!

Two springs.

Close view

It works!



Unfortunately, I can't upload video.
Last edited by notisjim on Thu, 31 Aug 2023 15:24:28 +0000; edited 2 times