this one drove me nuts for about two years.

i have a silca frame pump JIC the CO2 cartridge. gives me no joy.

see that chrome like handle? if it is not seated right then it will make a racket when you hit a bump. but since we seldom use the pump, it stays on the bike thus avoiding detection. when we swapped out the plastic silca pump head for the campy, the game was up for the loose, offending pump handle. and yes, i know i need a new paint job.