I don't know a thing about the mechanics of floor pumps, simple as they may be, I am simpler. I am trying to pump my tires with my usually dependable Specialized pump, and it gets jammed mid way and then no resistance at all to the bottom. Meanwhile its not getting air into the tires. It does read the pressure though.

Is the pump shot?

Take it apart. Lubricate or grease the rubber pieces. Reassemble.

Thanks... so it's likely not busted? Am I disasembling and lubing the whole thing or just the nozzle? Is this a known and predictable problem with floor pumps? I do use it everyday, but it's only a few months old.

If it's only a few months old, it may well be broken. But it's impossible to tell without doing some more research. If it's not broken and just needs some maintenance, taking it apart will be necessary anyway. And if it is broken, there's no harm in taking it apart to see what happened.

Pumps have rubber parts that need to be lubricated. I usually make it an annual thing. Perhaps your pump sat on the shop floor for awhile, though.

No prob, took it back to the store and exchanged it - a good store in that they deal with the Specialized warranty rigmarole, rather than my having to.

...also it was probably my fault the thing is busted. Early on I got into the uneccessary habit of using the converter bit thinking it was tighter and cleaner. I was told I probably busted the seal that way. Nonetheless, no hassles.

Thanks Spidy.

Seeing that it's relatively new I don't think lubrication is a factor (unless they never lubed it). Sometimes the rubber/leather washer falls off of the end of the pump plunger. If this has happened then you will have to remove the pump handle/plunger from the top of the pump and retieve the washers from the bottom of the pump barrel. You might need to get coat hanger and go fishing for it. If memory serves there should be a metal and rubber/ leather washers and a nut.