I fashioned a tool to remove the rear shock spring for the purposes of replacing the shock, installing a progressive spring or replacing the preload adjuster so I thought I would share it here.
Here is the tool I made out of things I had laying around the shop.
First you need to back out the set screw in the housing. A 2mm hex key is required.
Then install the tool and compress the spring to reveal the clip.
Make a mark to align the set screw so the adjuster will be in the proper position. I kind of forgot about it and made a mark on the shock body.
Remove the clip from the groove and release the spring tension.
Don't forget to put the clip back on the top of the shock before you attach the tool.
Release the spring by backing off the nut on the tool and remove the adjuster and spring.
Put on the new spring/shock/adjuster, whichever the case and reassemble in reverse order.
I was going to post this in the reference and FAQ forum but for some reason I am not allowed.