OK, you can try a few things;-
1) Push it in a little and then try extracting it. Sometimes 'working' them a bit can loosen them, so may need trying a few times, or
2) Remove the switch and with a small but solid 'lever' move it up a tad. If you have a look at the diagram, you can see that there are a few steps machined in to it where the switch screws in, you should be able to get under them to lever the shuttle out, even if just a tad, might be all you need (I've done this a few times),
2) USE CAUTION:- Fit the pistons and seals back in the Main Bore, leave the tank off. Plug up both outlet ports and blow compressed Air in to the Lower tank Port only. BE VERY Careful doing this though, be mindful where the shuttle is pointing, wrap a rag over it, but don't hold the rag in place. If this moves it, it will literally fly out, quicker then the eye can see, so be very careful and plan it properly.
New M/Cs are easily available if you do think you need to end up going that way.
