Abstract: A pump for feed-pumps of fuel injection systems for internal combustion engines having a manually actuatable element, which operates counter to the force of a restoring spring to effect an inward stroke of a piston which includes a valve tappet thereon that pushes open a ball valve to the fuel feeding system of a feed pump. In operation, a medium is positively displaced from a work chamber into the feeding system. Upon an automatic return stroke of the piston, a medium is aspirated from the fuel feeding system of the feed pump into the work cylinder and at the end of the return stroke the ball valve closes automatically. In its position of repose, the pump does not require its piston to be locked in place, and pressure impacts of the feed pump are prevented from reaching the piston.