Without seeing a picture of what you mean, I believe you need a new front lower ball joint.
The upper ball joint is bolted in with 10.9 grade bolts.
Here's a pic of the front lower ball joint install in the lower control arm.
If you mean Tie-Rod end ball joint or Sway Bar end link bolt, let us know.
1986 Fiero2m8 (LT1 NX / 4T60 Roadster Build)