well, something like this-
jack up, axle stands under something isnt the springs or axle(sills/outriggers depending on how good they are).
wheels off
handbrake cables/linkage(i don't know what it has, rod id expect at that age?) loosened and removed
clamp rear flexi and undo at axle end- stops brakes emptying the entire system of fluid.
prop off
shocks off- maybe measure up and see if they can also be flipped to under-axle without effecting scrubline first. if not youll have to shorten the drop-arms instead.
undo all the u-bolts/spring saddle guff- support axle with jack first. make a note of the order the bits fit in.
axle can now be dropped down and rolled out on jack. then swap the diff with it out, plus carefully cut/grind back the welds on the saddles. I usually find you can go 3/4 of the way through then whack em with a hammer and chisel to split em off without risking going through the axle casing. if you do have to cut through something, chunks missing from the brackets don't matter as much as chunks missing from the casing!
bits missing from the brackets can be welded up easily as they go back on. get the tubes cleaned back nice and round, brackets matter less. if you end up moving the shock brackets do them as well now. otherwise, youll need to remove the drop arms and cut and shut them the same amount as youve moved the axle up.
I then also usually undo the rear spring shackles and drop the springs to the floor. its easier to get the axle behind the car with wheels on and roll it under then lift the springs up to it then try to manhandle the axle in from the side over the top of the springs.
take the bolt out that holds the spring pack together on each side, flip it over so it goes in from the other side and refit.
loosely refit all the u-bolt stuff to the axle/springs, in reverse order, including the brackets youve cut off, just slot them in for the mo. youll probly have to take the wheels back off to do this so support it back on the jack, then jack the axle up on the diff to lift the rear end of the springs back into place and refit the shackles.
check the axle is centred, then do the u-bolts up to almost-tight, but so you can still twist the diff around by hitting it with a soft hammer.
refit the wheels and the prop, and drop down onto its wheels. adjust pinion angle as neccessary by hitting it up/down til prop is looking happy, then tack saddles in place.
jack it back up, wheels off, disassemble u-bolt bits so you can get in to weld saddles back on properly. then slap a bit of paint about on em.
now refit everything, inc handbrake, shocks, etc. but doint do the u-bolts up tight. take the hose clamp off and then bleed the brakes (should bleed up pretty easy as there can only be air in the rear axle portion of pipes), then drive the car down the road/drive/etc, letting it roll to a stop without braking, then lay under it and nip the u-bolts up. this will make sure the rear axle is tracking right.
thats only a rough guide, ive probly forgot little bits, but I think you should get the jist of things from that?
