98 Expedition EB 4.6L

Here is some info on my truck. I the 1st owner and have been good to the truck and the truck has been good to me. It now has 145K and have only changed basic stuff, oil, fuel filter, spark plugs, brakes, all fluids and one oxigent sensor. Great truck. Here is my question ? my parking brake is very low, almost to the floor and I don't seem to have any at all. Can any one tell me how to adjust the parking brake. My trakes are fairly new. Thanks

rear disk or rear drum brakes?