Office Chair Keeps Sinking? Here's Why, and How to Fix It
If your office chair keeps sinking, or simply won't stay up, the cause is almost always the same single part. Here's how to confirm it, what you can do yourself, and how to fix a sinking office chair properly.
Why does my office chair keep sinking?
The seat sits on a gas lift, also called a pneumatic cylinder. It holds a charge of pressurised gas behind a seal. Over years of use that seal wears, the gas can no longer hold your weight, and the chair slowly sinks to its lowest position.
The height lever only opens a valve in the cylinder. It can't repair a worn seal, which is why a chair that keeps sinking goes straight back down however many times you raise it.
Quick checks: is it the gas lift?
- The seat rises when empty but drops once you sit on it.
- The chair sinks slowly over minutes or hours, not just when you touch the lever.
- You may hear a faint hiss, or see an oily film on the cylinder.
- If the lever feels loose or does nothing at all, the fault may be the lever or the mechanism under the seat rather than the cylinder.
- If the seat tips, rocks or clunks rather than dropping, look at the tilt mechanism instead.
Can I fix a sinking office chair myself?
You'll find the hose clamp (jubilee clip) trick online: raise the seat, then clamp a clip or a length of pipe around the cylinder so it can't drop. It works as a temporary bodge, but it has real downsides. The chair is stuck at one height, the clamp can slip under load, and it scratches the cylinder.
The proper fix is replacing the gas lift. That needs a replacement of the right size (taper, stroke length and weight rating), a pipe wrench, and some force to separate the old cylinder from the base and seat mechanism. Our step-by-step gas lift guide shows how.
When to get it done professionally
If you'd rather not wrestle a cylinder out yourself, or you're not sure which one your chair needs, we'll do it for you. We match the correct gas lift to your chair's make and model and fit it in one visit, at home or in the office anywhere in London. While the chair is apart we check the base and mechanism too.
Common questions
Why does my chair sink even after I pull the lever?
The lever only opens a valve in the gas lift. If the seal inside the cylinder has worn, the gas can't hold the seat up, so it sinks again however many times you raise it. The cylinder needs replacing.
Is a sinking chair dangerous?
A slowly sinking chair isn't usually dangerous, but it is bad for your posture because you end up sitting too low for your desk. A chair that drops suddenly, wobbles or has a damaged base should be checked before you keep using it.
How long does a gas lift replacement take?
With the right replacement cylinder and tools, a gas lift swap is usually done in one visit, and most chairs are holding height again before we leave.
Does a hose clamp fix a sinking chair?
Only as a temporary bodge. A clamp fixes the chair at one height, can slip under load, and scratches the cylinder. Replacing the gas lift is the proper fix.
Office chair won't stay up? We'll fix it
Tell us the make, model and what the chair is doing. We'll give you a free, fixed quote before any work starts.