You need an internal spring compressor. You get it in the shock hole, IIRC. It may be that you need to do it in pieces, or part of it through the side with the spring at full droop, then compress it by jacking under the ball joint when you are done putting it in there. This saves a lot of needless tightening under pressure. It also must be noted that this is easier to do when there is an engine in the car. Then, when you get it pretty well compressed, lower the jack from under the ball joint. This will show you if you have it compressed enough to safely disassemble things. I would loop a chain loosely inside the spring and tie it off to the car before you pull out the spring. This way, it minimizes the danger should it all go wrong at the wrong moment, and may save your life. There is a lot of stored energy present in a suspension spring, after all.
