+1 on replace with a new complete unit.
Refurbing the rod is going to be challenging, and likely not cheap
, the slightest imperfection and it won't work properly/leak. And if the rod is bad off then what about other parts
If you machine the old rod to smooth it out, as considered in one post, then you will need to use non-standard sized seals
. That's going to be a PITA when you need to replace seals
and can't just go with the standard seal kit.
The rods on my Seastars are still in great shape after 14 years so a new unit, properly maintained, will last a long time...an old unit refurbed who knows?
Rods on mine are stainless. In that case, you could have a whole new rod machined, but again probably a significant % of new unit price