so after ignoring a bit of advice about upper control arms and whether to simply replace or rebuild them..... I think I will be pulling out my passenger side for the third time in 3 weeks this weekend to get it right- DOH!
New replacement repo UCA Bushings threads are actually slightly bigger diameter than the originals and so they bind when tightening so the bushing has not completely sealed the o-ring before it was very tightly torqued. Realised what was going on with the second set- drivers side and so had to use them to cut a new thread in the UCA. Now drivers has to come out to do the same. The 'replace the whole arm' was resonating a lot last Saturday about midnight along with some choice words!
Apparently the explanation I was told was the original tooling was probably worn or slightly softer material than today and so after doing thousands of UCA taps, the tooling diameter could have been slightly smaller even though the threads were ok. Sounds like a dodgy theory to me but wondering if anyone else has had the same issues when rebuilding original arms?