The last time I used a Silca pump was 30 years ago. Used it on a vicious dog and cracked the tube ... been a Zefal fan ever since.
There must be a trick to pumping a tire with it, because:
when I push the head on the valve, as far as it will go, the compressed air pushes the handle out on the backstroke.
when I push the head on, just a bit, I only get back-pressure when pumping
What is the correct way to mount the pump head over the valve ... and use a Silca pump.
Amir Avitzur Ramat-Gan, Israel
BTW: a seller on ebay (mgpicco) has very cheap NOS Silca pumps ... with silca heads.