If you are just trying to get to the shims on the UCA, all you need to do is loosen the nuts on the UCA inner shaft. No need to raise the car, or do anything to the spring. All you need is the wheels facing straight ahead, car's weight on the wheels. Of course, if the shims fell out, the nut is already loose or missing.
If the shims fell out it is alignment time, but do replace the UCA bushing first.
UCA comes out by jacking the corner up with the jack as far outboard on the LCA as you can get it. It is OK to remove lower ball joint grease fitting in order to get the jack on the ball joint. Wheel off, loosen upper ball joint nut (remove cotter pin) a few turns.
Pop the upper ball joint loose from the spindle. Two BFH, one in back of the spindle where the ball stud goes through, and the other to beat the snot out of the spindle from the other side will pop the stud loose. You will have to be aggressive to get it this way. Kent Moore makes a ball joint separator that will push the stud up. Or if you intend to replace the ball joint, a "pickle fork" driven between the ball joint and the spindle will work -- but it will destroy the rubber boot of the ball joint making replacement of the ball joint necessary.
Then remove the two nuts holding the inner shaft of the UCA. The studs for those nuts are pressed into the frame, so don't buzz the studs out with an impact. Only turn the nut. If the shims are still in there grab them before they fall and tape them together and mark which position they came from. You may have to push out one or more of the studs (guaranteed on the passenger side rear stud) to get clearance for the shaft.
Now all you have to do is replace the bushings and/or ball joint. There are a lot of threads on front UCA bushing replacement. There are a couple of ways to do it, and they have been explored. Good luck.