I found I did not have to un-do my shocks when lifting my van to remove shackles.
But that may vary with different vans.
I merely put the jack (with block spacers) under my trailer hitch and jacked until wheels started coming off the ground. But be aware this method can be tricky if you're not on perfect level smooth ground. Blocks can fly out if not perfectly square with load. Another method might be to jack up pretty high (under differential), place jack stands under frame, then lower differential.
Leaving the shocks attached, the drive side was easiest (lined up perfectly).. passenger side dropped a tiny bit too far (so just let the van down a little). You can flex the spring by hand enough to easily slide bolts though. I only needed 3 tools.. 13/16" wrench, 13?16" ratchet-socket, 7/8" wrench. It's actually metric, but this still worked for me. Job is about 15 min a side max.
It doesn't hurt to always be safe, even though you really don't have to get underneath. Once van is up in air (regardless of how you lift).. you should place jack stands under body/frame where it makes sense (rear axle will need to swing freely). Just do one side at a time. I placed my jack stands at the forward end of the leaf-springs under the perch.
Pretty easy job.
Again, do not pump the zerk fitting with petroleum based grease. As I said, I suspect this is what destroyed the urethane bushings in the first place. Apply silicone grease (supplied) by hand. Don't forget outward face of bushings that slide up into the body of van. You'll want to completely clean this area of former grease before sliding shackle back into place. I'm old school... gasoline on paper towels (or rags) make a great cleaner.. lol.
