Reply to "Pantera 06927"

All things- even precision bearings & axles- have tolerances. And with press fits, the assembly requirements are in the ten-thousandths of an inch range. A proper pressfit on axles is 0.0005" to 0.0008" larger than the bearings for that assembly. One simply cannot check this with a std calipers. I use extreme-pressure rear end lube or Lubriplate moly-grease on axles when pressing, and for really tight fits, its well to freeze the axle and heat the bearing to about 150F degrees before pressing.
The only thing I can think of for your lock-up problem is, the extreme press pressure bent the outer steel bearing retainer, and there's not much clearance between that retainer and the wheel-stud heads. Likely, the torque wrench was still trying to pull the nut down tight so it didn't 'click'; 300 ft-lbs is not enough torque. Around 450 ft-lbs is more realistic and is why one uses new nuts if they are the sliced ones that twist when tightened. Filing the scratches flat (but not out completely) on the scored new axle will work fine, as will selectively fitting a new bearing to the 'tight' axle. You may find a new bearing that FALLS ON- that obviously is on the other end of the tolerance scale! One thing with a press: do NOT use simple stand-offs on the brake rotor to back up the pressing: you will shatter the disc- as your mechanic found. I use a huge steel pipe cap 6" thick with a hole bored thru that just clears the axle flange and contacts the rotor on its curved edge, not on the braking surface. Others use wood or plastic stand-offs made the same way. I know of several owners- including vendors- that have broken cat iron brake rotors trying to disassemble.
Finally, drive or press out all 5 wheel studs before pressing an axle in or out; this removes about half the pressure required to assemble/disassemble a properly sized Pantera rear suspension.
Vented rotors will stabilize on a hard-driven Pantera about 200F degrees lower than solid rotors, so if your driving will be at Bathurst or other such, you'll need vented rotors on both ends and Porterfield R-4S brake pads, to keep from brake fade- especially with the deeply-embedded brakes on a GT5-S! On streets & highways with only occasional stops, either rotor will work fine. Hang in there- this WILL go together.