[old cruiser]

Place a jack under A arm with a little clearance , loosen nut on on ball joint but only unwind it a few turns this doing this give you some insurance that nothing will fly out and take your head off. Then you give spindle a few good whacks with a reasonably heavy hammer right where the ball joint stud goes through the spindle. You'll hear it release then remove nut and then slowly let the jack down and spring wil now be able to be removed.
1 more thing I nearly forgot before you let down jack tie up the top A arme so that it doesn't drop and stretch or rip you rubber brake line.
I've done heaps of cars this way with this style suspension and never had a problem. good luck