Early Gen1 Rear Shock Issues 98

Jul 2014
South Coast
Right help needed please people, as part of the pre-dyno shakedown I thought it appropriate to get the suspension, static sag etc set-up, sooooooo went to measure the max height and then settled height to work out rear sag and the shock seems way over damped, more so in rebound than compression, basically when push it down it does not recover back to its start point without me pulling it up. So shocks out and the springs off (Its an early Gen 1 with the blue Sachs Shock/ white spring), pulling and pushing the damper rod is really really stiff (no oil leaks on the seal or pitting on the damper rod) I expected it to be stiff but not as stiff as it is. The linkages are all rebuilt with new rollers/ pins and teflon washers and they are all free as are the top and bottom mounts on the shock itself. It could be a gas issue so would like to re-pressurise first,anyone confirm correct pressure for the nitrogen?

Worst case what options have I got for replacing, I believe the dogbone/plates differ from mine to later Gen1's