Help! I've got a 1991 Suburban that I'm replacing the rear springs. (one broke at the eye) I've got a pair of new springs on order but there's a problem... I'm having trouble finding the correct bolts to hold the springs on. The dealer says they are a 9/16" bolt. When I asked them if I could order them, the guy says they are $10 A PIECE!!! (I need 6 of them, four for the springs, and two for the shackles....That's $60!!! For @#!$ing bolts!!!!) Are these a special (shouldered) bolt, or can I just go down to my local hardware store and buy a grade 8 (hardened)9/16" bolt of the proper length?