Your question does not make sense to me so cannot offer much advice apart from the following:
To take apart a gas lift bar stool, you'll find that the three components, the base, the seat and gas strut are held together by interference fit and will simply need to be pulled apart albeit with some force. You may find that you can knock out the strut from the base with a hammer, but use a bit of wood to prevent damage to strut from direct hammer blows.
Rupert, June 2020
