How do you repair a 1950 takara belmont barber chair arm is stuck and wont go forward to lift or go down?

I have 4 takara chairs around the 50's vintage. 3 of them dont go up or down. I dismantled 3 of them and the hydraulic cylinder has seized. There was plenty of oil in them but the piston is stuck in the bottom of the cylinder. The cylinder is sealed at the end with a crimped end cap so the cant be repaired. I am going to drill a hole in the end cap and belt the piston out and see what happens. I have found out you cant buy parts for them!