Koken Chair Hydraulics and Age

I suspect you will have difficulty finding good drawings or parts lists for older equipment like this. If the lift cylinder has been dismantled, presumably it is now separate from the chair. I would take it to a hydraulics shop and have those folks look at it and advise on what you might need. They will be able to trace out where the oil is supposed to go, and what areas need to be sealed from each other. Good luck with your restoration project; I would think it can be successful.

http://cr4.globalspec.com/search/sitesearch?do=show&sort=textmatchrank&srch=barber%20chair&order=asc

With out some idea of where the grooves are in relation to the assembly it's hard to give a informed answer. Post some pictures.

But if it is like other small displacement cylinders that have double tubes. The outer being the reservoir the inner being the actual lift cylinder. The outer is usually screw theaded into the base to seal it and the gland is screw on to the top. The inner tube is seal with o rings top and bottom. As it is held between the base and the gland nut in ports which the o ring set.