Taipan Mutant Question - How to remove fill port dust cover sleeve?

I'm trying trying to remove the fill port dust cover sleeve on my Taipan Mutant. I have removed the grub screw/set screw, but the sleeve will only slide about 1/4". On my Taipan Veteran when I remove the grub screw/set screw the fill port dust cover sleeve just slips off. Any help would be greatly appreciated. I'm trying to get to the gage which I think has a slow leak.
 
I believe you will find the gauge is what's holding the sleeve on. If you can de-gas the gun, you might find a thin walled socket that will unscrew the gauge, then everything under it will be accessible.



Kindly 'Ol Uncle Hoot

PS: I can't swear to the above...just a memory of a memory. I'm not perfect, I think I made a mistake once before, although I could be wrong about that.
 
OK ... just did a total reseal on a customers MUTANT.







EMPTY OF AIR ... Insert two pins in the inner recesses next to gauge ( used the shank end of a #44 & #45 drill ). This locks the outer sleeve to the gauge body & rotating the sleeve unscrews the gauge from end block

Once gauge is off, loosening the small grub screw the sleeve pulls off.

At this point you can also easily unscrew the end cap assembly & service the filler o-ring and tube o-ring.



Scott S