I recently received one of these hand pumps in a combo package... But there's no pressure building when I try to use the pump. Air seems to leak out of the top by the handle, and there is this opening on the top with an o-ring around it... Am I missing a piece? See links for pics. Thank you for any advice!
https://goo.gl/photos/n9QJ5uXR4GQ4rYFA6
https://goo.gl/photos/YdMjJFDsKXHxcMRh9
https://goo.gl/photos/n9QJ5uXR4GQ4rYFA6
https://goo.gl/photos/YdMjJFDsKXHxcMRh9