Help! My Office Chair Keeps Sinking.

An office chair that won’t stay up sinking as soon as you sit in it is really frustrating. Usually it will stay up when you’re not in it and yet as soon as you sit in it down it goes.

Why does this happen and what can you do about it?

How a pneumatic gas lift works
This sketch shows what a gas strut looks like. On top is the button, it acts like an on off switch.

Sketch of an office chair gas lift.

When it’s off or raised it holds the strut at whatever length it happens to be at.

When you operate the height control usually with a lever or paddle it depresses the button and this turns on an internal control valve.

The pressure of your body weight then makes the gas in the cylinder compress so lowering the chair.

And when you operate the lever while lifting your weight the gas expands and raises the seat height.

So much for how it works, what’s going wrong when the cylinder no longer holds its position?

There are normally one of two causes, let’s look at them.

The gas strut is defective
Quite simply the strut is worn out. Due to wear it’s no longer able to hold its pressure when weight is applied. When this happens the best course of action is to replace it. Although it may be possible to apply a fix as we’ll see shortly. On to cause two.

The adjuster isn’t engaging properly
Frequently the cause of the problem is due to the adjustment lever not operating as it should. Levers can become jammed or misaligned and apply continual pressure to the button resulting in that sinking feeling.

Now we know what might be happening what are your options?

How to fix things
As previously mentioned a defective strut is best replaced. However, a new product called the chair saver offers a low cost solution this article explains how it works.

Where the lever is the culprit, there’s a good chance you can sort it out. Take a look under the chair and see if the lever appears to have become dislodged or jammed and try and push it back into place. It may be slightly distorted and just need bending to make it engage the cylinder button properly.

Where you’re in an office with the same model of chair in use, take a look at them side by side. Compare the 2 chairs for any differences it may well help sort out what is wrong.

And if that doesn’t work, the chair saver should work for this problem too.

Ultimately, if the chair is a number of years old, it may well be time to bite the bullet and buy a new one. This article explains what to look for when selecting a new computer chair.

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23 Responses to “Help! My Office Chair Keeps Sinking.”

  1. same thing happens to me.

  2. Are these chairs hydraulic or pneumatic? I thought they were pneumatic.

    I got a chair from someone and it does the same thing! It’s so annoying, lol. I use it at home, so while it isn’t a BIG deal, it’s still annoying. My son weighs 45lbs and he’s just at the right weight where he can move his torso up and down and the chair is like an amusement ride to him, lol. The chair works almost as if WEIGHT keeps it in position. The lift lever works fine, so I guess it’s the gas lift that’s broken, but like I said before, I thought these chairs were pneumatic.

    Aaaah, the mysteries of life. ;)

  3. Sounds like it needs a new gas lift, yes they are pneumatic. Mind you, your son might not thank you if you change it!

  4. some chair you can put a muffler clamp on the cylinder to lock it in place

  5. This is actually a very innovative idea. Assuming you can work out what height to lock the height at this could be a really simple solution for fixing a failing cylinder.

  6. Can you provide some insight on how that would be accomplished? Does the curly piece of plastic need to come off?

  7. I’m not quite sure what you mean, but if you are referring to the nesting plastic shroud around the gas lift, then yes you would need to remove it. It’s only there to hide the gas lift.

    You would need to get a clip of the right size for the diameter of the stem, so measure it carefully. I would definitely use a metal clip, rather than plastic and wipe off any grease on the gas stem around the area where the clip is to be located. Finally, make sure it’s real tight, it may not work but it’s worth a try.

  8. r,

    Great suggestion. I fixed mine with a screw-down type hose clamp. -S

  9. I fixed mine!Very quickly and esily.

    Here’s how I did it… keeping in mind I am very tall and like the chair set to the highest setting for a shorter person it may take more inginuative measurements.

    I measured how long the pneumatic sleeve (the outside part attached to the wheels)was.

    Then I measured down the length of the piston into the sleeve past that point so I was just below the base of the piston.

    Then I drilled a hole just big enough to hammer a stubby black handled screw driver into.

    The piston sits on the screw driver now and the screwdriver looks like just another chair control.

    The turning is a little stiff but the chair no longer sinks! Its perfect! Im going to Disneyland!

  10. Great tips…when I saw that the lever might be jammed, it just workied it back and forth and realized that while it pulls up, it never goes all the way back down. So I pulled it up, adjusted the height of the chair, then pushed the lever down all the way. Hooray..the chair stays up. For whatever reason, the lever just doesn’t automatically return all the way down to lock the chair. Pushing it all the way down myself did the trick…no sinking chair! Thanks!

  11. I also came up with a way to fix this chair problem… I rolled duck tape around the piston until the thickness of it increased to the point where it could no longer slide down into the housing (or whatever you call it). This stops the chair from sinking any further. I must have used about 2.5 yards of duck tape to get the desired thickness. I’m a 300 lb. guy too and it’s holding me fine! :)

  12. Well done with your duck tape fix.

  13. I am using the same theory as the duct tape method. Except instead of wrapping to the thickness of the housing. I put a ball point pen, on the piston with the point facing downward and wrapped clear packing tape around the piston and the pen. So far so good. Although I am wondering if the pen will break eventually. Some type of iron post like a screwdriver might work better.

  14. Little known uses for ball point pens! Well done Jane, let’s hope it lasts.

    If not a screwdriver is definitely worth a try.

  15. Mine had a small metal piece that kept the stopped the plunger from going all the way up. I just had to bend the metal piece about a quarter inch to allow the plunger to go up further and it works fine. I just needed a flat screwdriver and a small pair of pliers.

  16. Thanks for passing on this tip Eric. Glad you got it sorted.

    Duncan

  17. Update: it’s been 3 months and the duck tape method is still holding up pretty good. I noticed that the duck tape roll has migrated lower about 2 inches however, and there are shreds of duck tape under the chair from this shearing effect. But I’m still at a comfortable sitting height for my legs so I’m fine. :)

  18. Thanks for the Steevn, that’s pretty impressive.

  19. duct tape solution working great – even for 360 lb guy like me! Many thanks to Steevn.

  20. Good to hear this worked for your too.

  21. Similarly to Jane, I used the Pen Method. Only, I used 8 pens, also parallel to the piston/chair-tube. I them wrapped them with a good 8-10 twist-ties for ultra durability. My father uses it in the shop to this day; it was a very smooth roller so it’s great for rollin through one’s shop.

  22. I found that the button on the top of the cylinder was stuck. I followed this YouTube video
    https://www.youtube.com/watch?v=uiDby4FouwQ
    to remove the cylinder from the chair seat(I left it attached to the base/wheels.)
    I used a pliers to carefully twist and pull up on the button, (it moved about 1/2″) then I sprayed the base of the button with WD-40. I pushed the button down with my thumb and pulled it up, twisting with the pliers, multiple times until it became loose enough to pop up on it’s own. Then I popped it down and up a dozen or so times to work in the WD-40.
    Working fine for now. My guess is it will eventually get stuck again, but hopefully a little more wd-40 and she’ll loosen up again.
    You might be able to spray WD-40 on the button without dis-assembly. (Might be pretty tricky depending on how the chair is built – try bending the tip of the WD-40 tube so you can spray down along the side of the button.) Then just let it soak in and eventually loosen up. I didn’t try this, but just a thought on what might work and save the step of dis-assembly.

  23. Great video, thanks for sharing.

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