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How to fix and replace an office chair gas lift

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Fed up of your office chair sinking every time you sit down? It’s probably down to a broken or leaky gas lift. While these can’t be ‘regassed’, as we’ll touch on later, there is an easy temporary fix you can make or you can replace them altogether. 

This guide walks you through the steps to both fix and replace the gas cylinder in your office chair, and it’s a job that can be completed within around 30 minutes. In fact, you’ll wonder why you didn’t do it sooner!

Contents

  • Should you fix or replace the gas lift?
  • How to fix a gas lift
  • How to remove a gas cylinder
  • How to replace a gas lift

Should you fix or replace the gas lift?

Before we dive into the instructions for fixing or removing a gas lift, it’s worth figuring out whether a fix will work or whether a replacement is necessary, and we’d like to clear up a common myth.

A gas lift can’t be ‘regassed’ or refilled, as the cylinder is a sealed unit and so once the gas inside has escaped, there’s no way to top it back up. However, there is a good fix you could try before you go for a full replacement, so we will cover both in this guide. The fix should stop the chair from sinking all the time and is a good temporary solution until you’re able to replace the gas lift or invest in a new office chair. 

How to fix the gas lift on an office chair

If you need an immediate, temporary fix rather than a full replacement, a hose clamp (sometimes called a jubilee clip) will do the job perfectly. This will hold the chair at the right height so it means it’s no longer adjustable but it won’t sink every time you sit on it. 

  1. Choose the right height for your chair (and ensure it is right, as you won’t be able to change it afterwards)
  2. Carefully put the chair onto its side so you can identify the piston shaft. This is the metal rod that comes up from the base of the chair and into the seat mechanism
  3. Wrap the hose clamp around the piston shaft just below where it goes into the mechanism and tighten it as much as you can
  4. Gently put the chair upright and test that the clamp works as it should. The chair shouldn’t move down as you sit in it, because the shaft can’t move into the cylinder with the clamp in the way.

As we’ve said, this is a good temporary measure but it means you can’t easily change the height of your chair. Perhaps try out this fix while you wait for a replacement gas lift or until your new chair arrives.

How to remove a gas cylinder from an office chair

Removing a gas cylinder and replacing it is a good option if your chair works perfectly in every other way and you want to keep it. It could mean you get a few more years’ use out of your chair instead of disposing of it. 

Gas cylinders aren’t screwed or bolted into place. Instead, they’re held in place with a tight friction fit so you need to break the fit rather than unscrewing or unbolting the cylinder. This means a little bit of force is required. 

To do the job, you’ll need: 

  • A mallet
  • Some WD-40
  • A plumber’s wrench
  1. Extend the chair to its full height and then carefully turn it upside down so that the seat is on a stable surface, like a table, with the backrest hanging down towards the floor
  2. Spray some WD-40 directly on both ends of the gas lift (where it meets the seat mechanism and where it meets the five-star base) and then wait a few minutes for it to work its magic
  3. Use one hand to hold a leg of the chair base and the other to hit the bottom of the gas lift with your mallet. It might take a few gos and some force, particularly if the chair has been used for a few years. 
  4. Now the base is off, you need to disconnect the gas lift from the chair seat. Use a plumber’s wrench to get a tight grip on the piston shaft and gently wiggle it until the cylinder comes free. 

Note: if your chair has a plastic cover where the gas lift meets the seat unit, you should remove it once you’ve taken the base off but before you’ve removed the seat. 

How to replace the gas lift in an office chair

Once you’ve followed the above steps to take the old cylinder out, fitting the new one is quite straightforward. 

  1. Your old gas lift might have a concertina-style cover on it. You can take this off and put it onto the new one (it’s an aesthetic thing rather than a practical one)
  2. Fit the new gas lift into the hole in the seat mechanism, pushing it in quite firmly to get that friction fit nice and tight
  3. Refit the plastic cover you removed early (if required)
  4. Push the five-star base onto the body of the new gas cylinder, again applying a firm pressure to ensure it’s in fully
  5. Carefully turn your chair the right way up and test out your new seat, making sure the chair height is suitable for you. 

A note on buying your replacement gas cylinder

Before you buy a replacement cylinder, there are a few things worth checking to make sure it’ll fit once arrived. You should measure the length and the diameter of the old cylinder to ensure the size is accurate, but also check the type of base fitting. Gas lifts can vary between chair models and manufacturers, and an ill-fitting one won’t sit properly.