95 GM sqeaking

My wife's 95 is squeakin, and "moanin" when she drives it. If I just push up and down on car, it makes all the noises too. It's got new upper/lower ball joints, new tie rods both sides, new steering parts. Noise went away with parts install, but now about 8 months later, noises are back with a vengence! Any ideas? Bushing LOOK ok, but could be problem. Do control arm bushing need pressed on, or can I do them at home if they ARE the prob?

Well, i narowed it down to the UPPER ball joints. Turns out they weren't replaced when the lower ones were. (don't know why!!)