remove the nozzle/venturi assy, by removing the steering cable, reverse cable if you got one, VTS cable if you got one, then the 4-13mm bolts. Remove those, pop off the assy, and you'll expose the cone. Remove the 3-bolts securing cone, pop it off, tip trailer up as high as you can, to drain the old out, then dip trailer as far down, to refill, using the "set plug" in the cone, after you've re-installed it. MAKE SURE you dont lose the 2-little orings at the venturi to pump, where water ports are...