Fresh regulator pin / seat orings & spacer - valve still leaks from side

[Mueller]

Installed fresh orings/spacer on pin assembly. Unit still leaks from the side relief. It's an RT Pro, everything looks clean/straight/undamaged, pretty well oiled at this point :)

What should my next move be? Rinse and repeat a few more times to see if it resolves? Could there be other upstream issues that cause this leak or is it really the reg pin/seat orings only?

I do have a 2nd RT PRO valve here that works fine if swapping bits would prove out anything


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E: Followup:
Solution was to clean off the schmutz on the brass spacer between bellevue spring stack and the orings on the pin. I slipped that brass part off, cleaned off thoroughly, regulator "side" leak gone.

[vintage]

i can't tell you how many times i have had to pull the same pin assembly, take it apart and wipe the o rings down and then blow out the valve before the thing would seal.
if you have a magnifying glass you can check the o rings for nicks, just because they are new does not mean they aren't out of spec also you can check the seat area in the valve.

you might try switching the halves of this valve with the other one and see if it seals or not.