How To Install Your Replacement Aeron Lift

Posted by Sam on 27th Nov 2018

How to Install Your New Pneumatic on Your Aeron Chair

If your Aeron chair sinks whenever you sit in it, the gas cylinder (a.k.a. gas shock, cartridge, pneumatic, hydraulic, piston, lift) has gone bad. For installation of your replacement Aeron chair cylinder, you will need:

A mallet (preferably metal vs. rubber for more force) or hammer
A pipe wrench
A 5/32" Allen wrench
lubricant such as WD40

The top of the cylinder includes a plastic activation button- DO NOT remove it. It is needed to activate the lift lever. There is a black, plastic cap covering the button when you receive the cylinder- this can be discarded as it is only needed to protect the activation button during shipping.

Tilt your Aeron chair on its side and rest on the floor or table. Spray some lubricant where the bottom of the seat mechanism attaches to the cylinder, and where the five-pointed base attaches to the cylinder. You may want to let the chair sit for a few hours to a day so the lubricant works its way in.

Take your pipe wrench and wrap the jaws around the cylinder. Twist the cylinder downards (doesn't matter which direction) until it comes loose and remove the five-pointed base of the chair. You will most likely need to use some force as the cylinder has been in the seat mechanism for years. If you're still having trouble removing the cylinder, you may need someone to help hold the chair down while you twist off the old cylinder. Make certain the person holding the chair down is holding it down by the frame of the chair, and not by the chair arms as the chair arms can sometimes snap off. If you need even more leverage, attach a cheater bar (a metal or PVC pipe) to the end of the pipe wrench. Adding more lubricant and letting the chair sit overnight can also help. The cylinder WILL come off!

Turn the base upside down and rest 2 of the legs against a hard surface like a table. You may want to put a cloth between the table and the base to keep the base from scratching. Take your mallet and bang out the old cylinder. If the cylinder still won't come out, try using a hammer for more force, but be sure to take a small block of wood or plastic to absorb the blows between the hammer and the cylinder. Using a hammer directly on the old cylinder may cause the cylinder to collapse making it harder to remove it from the chair base.

Once the old cylinder has been removed, place the new cylinder in the five-pointed chair base. Take the plastic ring, and place it around the new cylinder. With the chair base and new cylinder attached, take the base and place the cylinder into the seat mechanism. Turn your chair right side up. Sit in your Aeron chair and test to see if the chair moves up and down with activation of the lever. If your Aeron chair moves up and down with activation of the lift lever, you are done!

If your chair does not move up and down with the activation of the lift lever, you will need to tighten the set screw. You will need a 5/32" Allen wrench. Please go to 1:55 of the video for instructions to tighten the set screw.

If your Aeron chair now goes up and down without activating the lift lever, you will need to loosen the set screw. Please go to 2:45 of the video for instructions. You will need to remove the plastic cover underneath the seat to expose the set screw.

Here is video for installation instructions for your Aeron chair cylinder: