The purpose of the pneumatic cylinder in your office chair is to allow it to glide up and down smoothly. If you can no longer lower or raise your office chair, chances are this cylinder has failed. You could go out and buy a brand new chair, but you may be able to save yourself some money by purchasing a new pneumatic cylinder and installing it yourself.

Instructions

1. Sit in the chair and measure the desired distance from the chair to the ground. Measure from the base of the seat to the floor and use this measurement as your guideline for the optimal seat height. Move the chair up and down if you can, then use a marker to indicate the appropriate spot on the cylinder.
2. Turn the chair over and use a pipe wrench to disassemble it. First, remove the clip and washer that hold the center of the chair base in place. Pull the base off slowly, catching any small parts that fall out as you do. Place those small parts in a coffee cup or glass to keep them together.
3. Set the pipe wrench on the main shaft of the chair and turn it to loosen the shaft. Pull the pneumatic tube free of the chair housing and replace it with a new one.
4. Reassemble the chair by replacing the parts you took off when removing the pneumatic cylinder and chair seat. Place the seat back in place and screw it tight, then move the chair to the desired position.