Double action pumps have been a chronic problem for quite some time. The older ones have been sitting around in warehouses for years which makes the rubber parts deteriorate, and it seems that the more recent "rebuilt" units have a huge failure rate right out of the box. Keep trying until you find a good one.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!