Barber Chairs and All-Purpose Chairs (also known as Reclining Salon Chairs) have a gas shock underneath the chair top which allows the chair to be reclined.
Lie the chair on its back to have better access to gas shock. Oil will NOT spill out of the pump.
Locate gas shock. It should look like this or similar (SEE IMAGE BELOW).
Every gas shock has at least one black stopper attached (SEE IMAGE BELOW). Sometimes, gas shocks have more than one of these.
If your range is too short, try removing 1 at a time for a longer recline. If there is only one black stopper, it is at its largest recline.