The rear axle is getting close to being complete, so I thought I would document a few things. First, I my goal was to have lockers front and rear. My options basically came down to ARB, which is the general agreement for locker choice - strong, reliable, etc. I didn't go that route.
Instead I had a spare rear axle from another '78 FJ-40 which was a semi-float, and went deep into the forums telling tales of swapping a 9.5" Toyota e-locker from the rear of an FJ-80. I was immediately intrigued. Down sides are not to use large tires (not planning on going over 35", and if the locker fails it tends to trap everything inside the axle). I probably shouldn't have been so interested, but the idea of staying Toyota was intriguing. For some reason I've always felt the need to do things a little different.
First step was the rear axle is a semi-float design, and the FJ-80 is a full float. So either an axle swap was required, or conversion to a full float design. Then I found a kit which converts the semi-float FJ-40 to a full float design from Front Range Off Road, utilizing the same spindle and outer components as the front axle. In one swap I could go to a FF design, add disc brakes and a locker. I was hooked.
So, I tore the axle down to the housing, cleaned, painted, and added a brace. Then bought the right length studs for the FJ-80 locker - it requires 2 long studs and 4 longer studs, with 4 regular length studs. Also used the gasket from an FJ-80 locking differential as a template to grind the necessary clearance for the locking mechanism (left hand side):
The two major components to the kit are adapter for the axle flange to spindle and new axle shafts, complete with the long spline inner axle for the e-locker.
Flange mocked up:
Next, the outer portion of the axle needs to be trimmed flush with the inner lip of the flange to allow the spindle to bolt on. This essentially removes the bearing and seal mating surface. No going back now:
The new axle seal is held in place by an aluminum insert which is installed in place of the bronze bushing in the spindle:
And axle cut with the adapter mounted: