There is a torque spec for the shackle bolts. I thought it was 35 ft lbs, but that's off the top of my head. My shackle bolt nuts are the crimped style so they don't back off when used with such a low torque.
Also, I always use synthetic disc brake grease from CRC on all my rubber and poly suspension parts including the spring eye, swaybar & shock bushings. It dramatically reduces suspension sticktion and prevents squeaks. It helps make my suspension a lot more compliant on the road too.
Be aware that there are some new types of synthetic disc brake grease out there now, but they don't have Moly, PTFE and graphite in them. They are just the synthetic grease.
