Repair of pushbutton toilet?

Is it possible to replace the cable on a push button toilet? The problem is when the the button is pressed the water flows into the cistern and straight into the bowl none stop. It never rises to float level. Is it possible that there may be a kink in he cable? because when I lift the top off the cistern the flow returns to normal ie up to float and cuts off. Thanks for any advice offered.

henpecked
July 2008