Carefully, disassemble all the parts shown...do all your work on a white piece of paper or cloth, so you can see all the pieces...Caution: There are two tiny springs...don't loose them.
Remove the black rubber gasket from the cap.
Remove the little screw with lock washer and flat spring. Note, the concave/convex curvature of the flat spring for when you reassemble.
Picture after removing the top lock key swing cap, screw, lock washer and flat spring.
Another picture of the screw, lock washer and flat spring removed from cap.
Here's the flat spring mentioned above.
Another picture...see the difference?...
Cap and top lock key swing cap,
Top side of the cap and top lock key swing cap,
While powder coating, I put everything back together, not to keep everything in one place but to fully understand how to reasssemble the cap. Held it all together with some Scotch tape.
Looking at it from the top side.
I always use baggies to hold all the loose parts while I work on anything.
Just a picture of the powder coating oven. Top lock key swing cap on the left and the main cap on the right.
Finished powder coated cap and top lock key swing cap,