1. Remove the core plug. Do that by poking a hole through it with a hammer and small punch, say about 3/32″. Now with the punch still in the hole, rock it to one side, which will lever the core plug out.
2. Push the valve pin out through the opening you just created. A spring will come with it. Pick the o-ring out of the hole.
3. Where the pin was, is a small brass washer. Lever it out like you did the core plug. With the brass washer out, you will see the teensy o-ring. Pick it out.
4. Put a new teensy o-ring in, followed by the brass washer. “Stake” the washer in by upsetting the aluminum around the washer with a hammer and screwdriver. It doesn’t take much, just enough to sort of dent it. You will see how it was dented (staked) originally.
5. Back to the core plug end, put in a new o-ring, followed by the pin and spring.
6. Now, the new core plug. Insert a new one, dome side out. With a hammer and suitable large flat-ended tool. flatten the dome till it is flat. Warning, don’t go beyond flat or it will loosen up again and fall out.
7. Replace the o-ring behind the air vent pin in a similar fashion. You know how to do it by now.
8. I could do the whole job in less time than it took to type all this.
