If it is an emergency car tire pump, and you were using it on a decent sized chamber, it stopped because it overheated and something melted.
Id say thats what happened, mine melts and sticks coz the valves a sh*ty plastic peice of crap if I'm continuosly pumping over 120psi. If you can accsess the valve drill it out a little, this works wonders for me. Theres now less friction which melts the plastic and its 10x easier to pump. It used to max out at 110psi now it can pump to 150psi....if needs be