Happy Thanksgiving! As the turkey roasted, I snuck out to the garage to tinker.

Most coilover kits for the Mazda6 include adjustable perches UNDER the rear springs. Unless you are a "set it and forget it" kinda person, I don't find these very convenient. Also, when setting corner weights, you really need to be able to adjust the spring heights without jacking up the car. So here's my version of adjustable rear UPPER perches. For each side, you need two jack plates (just a 5" dia plate with a big nut welded to it) and a jack screw.
Here is the stock suspension:


We remove the rear hub assembly and the spring:


Here's the subframe upside down:

Remove the control arms and radius arm:

Remove the bumpstop and spring rubber:

Next we cut off the spring guide:

Then grind it smooth. We need a flat surface.

Flip the subframe back over. Here's the top view:

We need a 1-1/2" hole centered over the hole we cut below:

Flip the subframe over again. This pic shows what the jack plate looks like - just a 5" plate with a nut welded to it. To the right you see I have one clamped in place with the nut centered in the hole. It will be welded in place to the top of the subframe.


Flip the subframe over again. With the top plate welded in place, thread a jack screw thru with a lock nut.

Flip over again. Here is the lower plate threaded onto the jack screw. This plate will be welded to the jack screw and will move up and down with the screw. The top of the spring will rest on this plate (i will be adding a spring retainer so it can't slide around).

Top side again. The jack screw will pass thru a hole in the trunk floor and will be adjusted using a 1/2" drive ratchet.

There you go - still plenty of work to do, but I think it'll work quite well.
