Originally Posted by biker128pedal

When you mean stopped working can you be more specific? Does the air from the tire flow back into the pump pushing the handle up? If so above is correct and the check valve is stuck. If only six months old, you got it from your local shop and are on good terms, take it in and see if they will help under warranty. If not you’ll need to figure out how to clean and lube the check valve. I have a Joe Blow pump I had to take apart and do this. Just Spraying silicone worked for a tire or two.