You don't need to remove the spring to replace that #4. The spring only bears on it through the spindle. When I did my lower ball joints, I used a hydraulic jack under the lower control arm. I put it in place, jacked it up slightly, removed the nut for the upper ball joint, lowered it a little and with a couple of taps the spindle is released. #4 is now easily and safely accessed. Bear in mind the wheel and what not were all removed prior. A link to my post on the matter is below.
My Ball Joint Thread