[anijet]

My memory isn't 100% but IIRC from when I changed the riding height of our rig, the shackle bolts have serations near the head that bite into the shackle to prevent them from truning in the shackle. This is so the shackle holes won't wear out but rather the rotating motion is between the bolt shank and the spring where there is a much larger contact area. If this is the case, you won't be able to turn the bolts unless you strip the shackle hole where the serations are. You would need to take the nut off and push the bolt out to clear the serations.