I think you will find that sway bar setup is working against the traction bars to cause the bind.
Did you get the Datsun 240 C or 260 C models over there the sway bar on those H190 models was a neat setup that fitted to the front of the diff housing and curved over the diff Centre a very neat setup, quite narrow so applicable to a 1200 chassis

My Nissan Stanza (Late 510) ran full works suspension including the works H190, that car was awesome on tarmac but it used boxed Holden Torana XU1 lower arms and also had a panhard rod fitted the standard diagonal upper links used works hard rubber bushes, As I have experienced binding even when well greased with delrin or nolathane type bushings and rod breakage with models such as the 1600 Toyota celica because the upper suspension rods were 13mm diameter solid rods not tubular with more surface area where welded to the bush housings all points to think about with suspension changes and too solid a bush transfers loads they could not handle

I assume you are running a 1500 Ute H190 those run tapered wheel bearings with shim adjustment and the axles butt up against a rubbing block in the Diff centre a good setup for a rear disk conversion as they do not suffer endfloat and pad knockoff, Also it is nice that when you machine the axles to get rid of the six stud pattern you end up with a blank axle for a normal Nissan 4 bolt stud pattern to be applied

I'm running the 510 wagon rear housing with 240z aluminum drums.

As for the sway bar, that set up was on the car with the H145 and traction rods and it did not do this. If there is a bind I suspect it was caused by my eliminating the long end links. We shall see.

Tom