OK. SO here's the rough procedure for replacing the rear springs without removing any MAJOR suspension bolts, like the ones that are seized in their bushings. But first, a safety precaution: This procedure involves compressing springs. A compressed spring is potential energy. This energy can be instantaneously converted into kinetic energy in the form of a high-velocity spring or spring compressor parts if something fails. DO NOT let either end of the compressed spring ever point toward your body and never drop a compressed spring. Wear safety glasses. If you don't have experience with spring compressors, pay an experienced person to do it. Your unborn progeny will appreciate it. You have been warned. Proceed at your own risk. These springs were my 13th and 14th spring replacements on various cars over the years.
1. Jack the rear of the car up, both rear wheels off of the ground, remove wheels. You did remember jackstands and blocked the front wheels, didn't you?
2. If you have rear disk brakes like I do, remove the calipers and set aside. The disk brake hose isn't long enough. If you have rear drum brakes you're on your own.
3. Remove one of the shock mounting bolts, either the interior upper or the exterior lower, on both sides. I was actually able to get my lower ones out. This gives the suspension more downward travel.
4. Remove the rear sway bar links on both sides, again this gives the suspension more downward travel. Astonishingly, mine came right off.
5. Install the OEM 27035 (OEM is a brand) spring compressor pictured in the red plastic case above, claws at the top and spade at the bottom of the spring. roosterst points out that the lead screw is too long. This is remedied by putting a 3/4"-drive 15/16", DEEP, IMPACT socket over the lead screw between the thrust washers and the spade. Put the 3/4"-drive end of the socket toward the spade. The socket nestles nicely into the pocket milled in the back of the spade. I got this socket as part of a set at Horror Fright Tool for $54. Expensive? No. Just think about using a Sawz-all to cut all those suspension bolts. Best $54 I ever spent. You need to have between four or five spring turns or three or four spring spaces in the compressor. About two inches of total compression should do. Keep your head out of the wheel-well while compressing the spring.
6. Have an assistant put a 3'-4' long 2"x4" over the top of the leading arm and underneath the rear subframe. Ford actually designed in brackets on the suspension specifically for this. You will recognize them when you look. Have your assistant use the 2"x4" to push down the suspension as far as he/she can.
7. Reach in and push the rubber spring isolator up off of the top of the spring and push it back up into the upper spring perch. If left on the spring it will prevent you from getting the spring out. The compressed spring will now be easily tipped out and removed.
8. Have your assistant release the suspension
9. DEFUSE THE BOMB! Immediately uncompress the spring. ALL tension must be removed from the spring before removing the spring compressor.
10. Reach in and remove the rubber isolator from the upper spring perch.
The assembly is pretty much exactly the reverse of removal. Two tricks: roosterst points out that this spring compressor doesn't like to stay well-centered in the spring when it's out of the lower control arm. This can be troublesome on assembly. A piece of old tire tread cut to size will keep the socket and lead screw centered inside the spring well enough to get it into the lower control arm. Second: Put a 1/2" long by 5/16" diameter bolt up into the drain hole in the bottom of the control arm to keep the lower end of the spring from covering the drain hole. Be sure to orient the bolt so that you can remove AFTER the new spring is installed. Be careful rotationally orienting the spring to be off of this bolt and correctly inserted into the upper isolator. While the spring is out be sure to clean the pockets in the lower control arm. They fill with crud. I cleaned the rust and scale off, too, and painted with Rust-o-leum while the springs were out.
Thanks to Mike_Mac for being the pioneer on this and roosterst for posting the pictures.
Good luck and safety first.