There has been much info in the past on the cause of waterpump failures. The cone is real. It is a thin stainless steel cone that is "metal staked" to the aluminum housing. It is in close proximity of the impellar blades to create the suction. If it breaks loose it will aggravate, or cause the failure, however many impellars have broken apart without the cone coming loose.
When you replace the pump, check out the cone. Put your finger in the center and give a little tug. It should be tight. If it's loose, or falls off, you will need to replace the whole pump housing, and that's only available from Ford dealers or parts supply online. The new Ford unit should have the "improved" plastic impellar. In any case, don't leave a loose cone alone, even with a metal impellar.
