I've now had two floor pumps 'break' in use, a Beto and a Vandorm, the latter on the first use. Both are dual Presta-Schrader. Both 'broke' while attempting to inflate a Vavert 700X28/35C Presta inner tube in a Continental Ride Tour 700x28C tyre. The tubes are on the big side for the tyres, but this hasn't been a problem in years of use. The maximum recommended pressure on the tyres is 70psi, and I now realise that when the Vandorm pump broke I was applying around 100psi of pressure. (I'm not very bike savvy.)
Now the situation with both pumps is as follows.
- If I raise and depress the plunger with both nozzles uncovered then air flows freely out of both nozzles.
- If I attach the Presta nozzle to an inner tube and raise and depress the plunger then air flows out only through the Schrader nozzle.
- If I cover one nozzle with a finger and raise and depress the plunger then no air flows out of the uncovered nozzle, but I can feel air pressure on the finger over the covered nozzle. This seems odd, because it seems to be the opposite of (2).
All of this seems to be independent of the position of the lever.
Does anyone know what might have happened, and if it's fixable?