Why Does My Office Chair Sink?

Have you been experiencing the sinking feeling lately, whenever you sit down on your office chair? The comfort level seems missing, and you are left wondering,” What causes my office chair to sink?”

You should address this issue quickly as it affects your body posture and productivity at work. However, you need not worry, as it happens to every chair after a few years of rigorous and frequent usage.

Read on, as this article will broaden your understanding about office chair working, detailed reasons for sinking chairs, and practical ways of fixing the sinking chair.

Why does my office chair sink?

Your office chair sinks simply because the chair cylinder has lost its capacity to lift. The sinking feeling is a widespread occurrence in office chairs, and it is attributed to the improper functioning of the pneumatic valve used for adjusting the seating platform. A pneumatic cylinder uses pressurized air for controlling the height of the chair.

However, after a few years, the cylinder fails to maintain pressure due to leakage from damaged seals. This causes the office chair to sink.

Over time, the excessive usage of the office chair wears out the seal in the cylinder and causes it to leak. Now that you are aware it is the cylinder responsible for your sinking chair, what would be your next steps for fixing your sinking office chair?

Keep reading this article till the end as it discusses the pneumatic system in office chairs and step by step DIY ways to fix your sinking chair.

Pneumatic System

Pneumatics are widely used heavy pieces of machinery that use compressed air for enabling movement. It largely depends on the constant supplies of compressed air from an air compressor for optimal functioning.

In pneumatic systems, the air compressor sucks in air and stores it in compressed form in a high-pressure tank. This compressed air is passed via a series of valves and pipes for causing the smooth movement of machinery.

A pneumatic system is considered a cheaper, lighter and cleaner system as compared to the hydraulic system. So, let’s explore the pneumatic system in the office chairs.

Pneumatics in Office Chairs 

The pneumatic element of modern office chairs makes them smart chairs. It provides easy adjustment for changing the seating arrangements of your chair.

A pneumatic office chair comprises a single-acting cylinder with a spring filled with air. As the piston moves out of the chamber, it expands the air inside the chamber and results in the lowering of the seat. When the cylinder fails to function, it causes your chair to sink.

How to fix an office chair that sinks?

If you want to restore the full functions of your office chair, you can purchase a replacement cylinder. However, this could be as costly as replacing the sinking chair with a new one. Instead, you can try the following DIY methods for fixing your sinking chair.

Ensure that the components of your office chair that support the cylinder are functioning properly. For example, keep the lever well oiled. The two popular methods for fixing an office chair include the PVC pipe method and the hose clamp method.

The PVC Pipe Method

Begin by measuring your chair’s cylinder. To do so, pull down the plastic skirt cover over the metallic cylinder. Next, hold a ruler horizontally across the cylinder for estimating its diameter. Also, note down the length of the cylinder when the office chair is at your desired height.

Buy a PVC pipe of appropriate length that easily fits over the chair’s pneumatic cylinder. This pipe should be equal to or slightly larger than the cylinder diameter. In general, PVC pipes with a 3.8 cm (1.5 inches) diameter works great with most chair models.

Ensure to buy a straight pipe of enough length that extends from the wheelbase to the chair seat when your office chair is at the desired height. You can work with smaller pieces of pipe rather than using a one-piece pipe.

Another alternative to using pipes is to use a tall stack of plastic shower rings. These rings are easier to install and provide cheaper ways, but these may not be strong enough to support your weight.

Use a saw for cutting the PVC pipe lengthwise. Use a vice to secure the pipe and cut through it from tip to tip on one side.

In the end, you should get a pipe with a slit instead of two half-pipes. Ensure to wear a mask while cutting PVC pipe to avoid inhaling its particles.

If you don’t have tools like a saw or vice, keep the pipe intact. Remove the wheels of the chair so that you can slide on the pipe.

Pull down the plastic skirt cover to reveal the metallic cylinder. Snap the cut PVC pipe onto the chair cylinder by pushing its slit side against the cylinder. It should prevent the chair from sliding down by holding it in its place.

If your office chair sinks very low, you can add more pipe pieces for snapping to raise it and adjust the chair’s height to your preferred height. This way, you cannot lower the chair again without removing the snapped pipe. So, choose the desired height carefully.

The Hose Clamp Method

As most of the office chair cylinders are covered by a plastic tube, pull down the plastic skirt cover off the cylinder to reveal the extendable metal cylinder underneath.

Adjust the chair’s height as per your preferred height. You need to set this height precisely as you wouldn’t be able to make height adjustments to your office chair after this repair. Ensure that the seat of the chair is in level with your knees in a standing position.

Lay the chair on its side if it does not stay up. Remove the plastic skirt covers at this height. To do so, turn the chair upside down and use a screwdriver for pushing the retaining clip at the base. Follow it by removing the wheels and skirt cover. Now, set the wheels back.

Buy a 2 cm hose clamp from a nearby hardware store for wrapping around the cylinder.

Loosen the hose clamp’s screw and pull out the end of the belt. Wrap the hose clamp around the cylinder. Ensure that the clamp is tightened firmly so that it can hold the chair up.

You can further enhance the hose clamp’s grip by wrapping a rubber strip or few layers of duct tape around the cylinder.

Ensure to do wrapping at the highest visible point on the metal cylinder. Moreover, you can also use sandpaper for scuffing up the area on the cylinder.

Slide the hose clamp upwards towards the top of the cylinder for tightening the clamp strongly. Ensure that your chair is placed at your preferred height. Once you have tightened the hose clamp, rotate the screw to fasten it firmly.

Check if your chair is being supported well by the clamp and unable to slide down past it.

The in-built height adjustment of your office chair does not work. You can adjust the clamp by sliding it lower or higher as per your preferred height.

To improve the grip of the hose clamp, you can use a strip of rubber for fastening it over the clamp.

Replacing the Cylinder

Using the PVC pipe method and hose clamp method are the temporary methods for fixing the sinking of your office chair. Unfortunately, these methods don’t allow you to adjust the height of your chair, and you can only sit at one single preferred height.

If you want to give a more professional fix for your sinking chair, you may consider replacing the cylinder. However, replacing your office chair cylinder is an expensive affair. If budget is not a constraint, replacing the chair cylinder is a great option.

It may sound complicated, but replacing the chair cylinder is very simple. Moreover, it fixes the sinking problem and leaves your chair looking brand new for another 5-6 years.


Preksha is passionate about writing articles that will inspire readers to make better choices. You will find her eating desserts for lunch, dinner and any time of the day. Also, she is the chief playlist engineer for any road trip.

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