i'd first just fill them and see fi the fluid holds, the pumps might have stopped in a closed position. i've heard there is a way to make this happen. i'm not that clever. otherwise, you can put a mini c-clamp on the line above the pump, or pull a union going to the pump and plug that. if you can, from the union, jet some cleaning fluid down into/through the pump if possible from the cap tube union. the pump can gum up over that long and you'll also have to hassle with a pump that doesn't pump well.