If you look around the internet, there is a lot of advice and conversation around castor correction for the front radius arms following a spring lift. However there is a lot less discussed about rear axle correction. Clearly "castor correction" does not apply to the rear but there is still an adverse effect due to a spring lift. There are two main effects, the nose of the differential is at the wrong angle which increases the angles the propshaft has to cope with and the spring mounts are not aligned top and bottom resulting in "banana" springs.

The key to a good suspension set up is balance and stability. Over stretching in any direction achieves very little. Ok so the vehicle may seem to have amazing "articulation" but if the tyres are not generating traction (ie pressing on the ground) it does not matter how far they have stretched to touch the ground. Bump stops are a way of protecting the suspension from over compression on one side and the tyres from rubbing inside the wheel arch. Therefore, with a new set of springs and shock I also have gone for bump stop extensions 

Work has continued over the last couple of days with the re-assembly. First the differential was replaced. I ensured the filler and drain plugs were removed (because this would have been an ideal time to "unstick" them if they had corroded in position) and then cleaned up the housing face.

I then coated the face with sealant, lifted the differential into place and bolted it up.

​As you can see from the pictures showing the "orange" springs, I was supposed to be creating a lift based on 3" (or 75mm) components from Trailmaster. However I must have accidentally sold the shocks I had put aside. Therefore for now I have fitted a pair of Rough Country N2 which I still had around from when I sold them.

So a miracle occurred and I did some more work on my Jimny today. First of all I repaired the ARB air locker tube that had been damaged. The threads had been pulled out in the brass mounting so I had purchased a repair kit and refitted the fitting. 

You can see the original damage in this article - https://www.bigjimny.com/index.php/bigjimny-blog/problems/entry/812-arb-air-line-repair and the photos below show the new parts alongside the old.