Most beep bilge sailboats mount their bilge pumps on a shelf type fitting that will bring up the pump and float switch as it is pulled up. If yours doesn't do this, that means that you will need to build one before replacing the pump and switch in the bilge.
Without the aforementioned unit, you'll probably have to pull the hose to pull up the pump and hopefully, the float switch. I'm a fan of the largest capacity pump that can be installed in a deep bilge, because the head on the exhaust hose is probably long enough to cut the pump's output by half, if not more.