1920s Barber Chair Hydraulic Problem!

I just pick up a 1920s Emil j. Paidar barber chair that I'm restoring. The chair didn't pump up or spin. I finally dislodged it to spin and then started to pump up. Got about a half inch up and the pump arm jammed up again. Now it won't release to go down, up or spin. My question is how do I get to the piston? There's a 2 inch hex nut on bottom of the chair and piston but does not budge. I'm sorry if I'm not leaving enough information but I really am not sure what I'm doing. Seemed like a lot of knowledge on this site. Thanks