While out driving a loud clunking sound started coming from drivers side rear when going over bumps. Jacked the car up when got home and noticed the drivers side rear lowerering bolt was not under tension and could be moved by hand (passenger side rear was normal). The PO lowered the car with aftermarket bolts and I just recently replaced the shocks and end links. Has the rear spring failed?

Thanks, I had it up on jack stands to inspect and removed the aftermarket lowering bolt. Suspect it has been going bad for awhile and the new Bilsteins and end links finsihed it off. This is an 01 C5Z with around 25K miles but guess it is an usage issue not mileage. Looks like I will be replacing a spring.

Thinking the same thing as I was figuring out what a new spring is going to cost. Going to get the front up on jack stands and inspect the front spring as much as possible. If that spring is also going bad it may make that decision easier since a set of Alden coil overs is not much more than both springs.