[bruceincam]

The objective of the spring spreader is to transfer the tension from the shackle bolt in the spring eye to the spring spreader itself. After you've done that, you can begin to tap out that spring eye bolt. It doesn't take very many "turns" of that nut on your spring spreader to accomplish that task. I don't know exactly how many turns it takes to do that but try a couple of full turns on each nut and then pick a shackle and see how easily it wants to be tapped out. If you can't move either shackle bolt, try another turn or two of the nut. Once you've removed one of the shackles, you can be sure that you have all of the spring tension on your spring spreader.

From my own personal experience, I'll offer my opinion that it's a lot easier to get the shackles off if the whole rear end is out from under the car. Be careful and mind all of the cautions that you've read. There is a lot of energy stored in that spring. If you do remove it from the car, use C-clamps to hold that spring together.