I've just gone from a hardtail with a coil fork to a new FS with air
shocks on both ends, and I must be missing something because I can't
get air into the shocks. I have a brand new SKS shock pump with a
screw-on fitting for the Schrader valves on the shocks. I pump up the
shock to the desired pressure (or a bit over). Then when I go to
unscrew the pump fitting, most - not just some, but most - of the
pressure escapes from the shock while I'm unscrewing it. Like, for
example, it will go down from 8 bar to 2 bar. In the case of the small
SPV chamber on my Swinger rear shock, it ALL escapes. (I press on the
pin in the center of the valve and no hiss.) Reminds me of the useless
tire pumps of my childhood.

I have read some other posts on this and everyone says "Oh, you're
just hearing the leftover air in the pump hose escaping." No. When I
check the pressure using a tire gauge, or by observing sag, I can see
that there's hardly any air in the shock. So I have two questions:

1) With a screw-on fitting like this, why WOULDN'T you expect all the
air to escape as you're unscrewing it, given that there is a
significant period of time during which the valve is still depressed
(allowing air out of the shock) but the fitting is already loose
enough to let air escape around the threads of the valve stem? Isn't
this precisely why all tire pumps now have the flip-a-lever style of
seal?

2) Is there some special technique that I'm supposed to use to keep
this from happening? What am I missing? What's the secret formula?

Thanks!
- Tony