So if Im lookin at this right. The nut at the end of the A arm rod, The four bolts on that rectangular attachment point, Then pull the bolt, (all the way or just far enough to clear?) back from the A Arm???
There is no A arm in the rear, just terminology, its the swing arm.
1. Loosen the big nut on the end of the axle while the tire is on the floor, sometimes you have to strap around tire to keep from spinning, I don't like using park. Then jack up and make safe and remove wheels.
2. Remove torsion bar bolts and bar. Also on the passenger rear, remove single nut and drill out rivets to caliper brake line, then remove caliper and hang out of way.
3. Get jack stands under rear swing arms both sides.
4.Remove lower shock bolt, loosen top one, tie up shocks out of way.
5. Remove big nut on ends of shaft.
6. Remove long bolt and nut from swing arm at the frame. Have help here if possible, heavy and jamming fingers is possible.
7. Rotate swing arm up and slide of end of shaft carefully and straight.
8. Reverse for assembly, follow torque sequence for torsion bar, mount caliper, put nut and clamp back on brake line and rivet back the other clamp.
There are seals on the swing arm pivot, spacers and washers, seals on the shaft joint through the swing arm, be aware, clean the and the contact points, look for dirt etc. Does not hurt to have spare seals around just in case.