Originally Posted by
pakossa
Is there some special secret trick to getting this thing to work? Or is this just something that takes time to get the hang of?
Frame pump or track pump?
Regardless, rotate the Presta valve to where you can get a solid connector for the chuck (usually Up on a frame pump) and release "a bit" of pressure to clear the valve, seat the chuck and have at it.
Keep a firm level head on a frame pump with the off-hand, on a track pump give it the willie.
Many/almost-all of these devices are decades old and require proper maintenance of the chuck seal and/or leather plunger.
These are still available OEM, just ask how/what:
https://silca.cc/pages/contact