I ve just fitted your hydeo lines to my s14a. All fits ok. I ve fitted them the same way in your picture keeping abs pump and standard 14a t piece and the hydro doesnt lock the rear wheels. Do I need to change the rear t piece?
All boils down to 1) how good your rear brakes are (caliper condition, pads/discs) 2) how you're using it.
Does it feel ok? As in firm when you pull it?
Apparently the rear T has a restrictor in it, never looked myself though.