i installed a new check valve today. i fished around inside the pump outlet but COULD NOT find any pieces of the destroyed valve. i found this very odd, but installed the new valve anyway. it still is pulling way too little when cold-- only 5". the valve however, did seem to make a difference when throttling up.. the vac when throttling up when cold will go up to 15", and the new valve seems to hold it there better than when there was no valve. but at this rate, i need a new vac pump