How to Replace an Office Chair Cylinder

On this page (8 sections)

1. What tools do you need to replace an office chair cylinder?
2. How do you remove the old cylinder from the base?
3. How do you remove the cylinder from the seat plate?
4. How do you fit the new cylinder?
5. How do you test the new cylinder and adjust the height?
6. What else should you check while the chair is apart?
7. How do you dispose of the old cylinder safely?
8. Which cylinder should you buy for your chair?

To replace an office chair cylinder, flip the chair over, tap the old cylinder out of the base and seat plate, then press the new cylinder into both. Most chairs need a removal tool and a rubber mallet, not a full rebuild.

The whole job takes about 20 to 40 minutes and saves you the cost of a new chair. The cylinder is the gas lift that lets you raise and lower the seat, and when it wears out the chair sinks under your weight or stops holding height.

This guide walks through how to replace an office chair cylinder, what to check before you buy, and how to fit it without damaging the base.

What tools do you need to replace an office chair cylinder?

You need a cylinder removal tool, a rubber mallet, and a flat work area for most chairs. A kit with a purpose-built removal tool is the easiest route, because the tool grips the cylinder so you can tap it free without prying at the base.

Some chairs let you remove the cylinder with a pipe wrench and a block of wood, but that risks crushing the old cylinder or scratching the base. A removal tool spreads the force more evenly.

The Office Oasis says it invented the first cylinder replacement kit with a removal tool in 2016, and its kit includes the tool, gloves, and step-by-step instructions. Set the chair on a blanket or cardboard so the base and casters don't scratch the floor.

Wear the gloves from the kit, since the old cylinder can have sharp edges or grease. Keep a tray nearby for small parts like the seat plate bolts.

How do you remove the old cylinder from the base?

Flip the chair upside down and separate the base from the seat. Hold the base and pull the seat up and away; on many chairs the cylinder simply lifts out of the base once the seat plate is free.

If it's stuck, that's where the removal tool comes in.

1. Turn the chair over so the casters point up.
2. Remove the bolts that hold the seat plate to the underside of the seat.
3. Lift the seat off and set it aside.
4. Grip the base and pull it away from the cylinder.
5. If the cylinder stays in the base, use the removal tool and a mallet to tap it out.

The cylinder sits in a tapered socket in the base, so it wedges in over time. Tapping from the top of the base, with the tool gripping the cylinder, breaks that grip.

Don't hammer directly on the cylinder shaft, because it can bend.

What if the cylinder won't budge?

Soak the joint with a penetrating lubricant and give it time. A cylinder that has been in place for years can seize, and force alone may crack the base.

Let the lubricant sit for a few minutes, then tap again with the removal tool in place. If it still won't move, check that you've removed every bolt and that the base isn't bolted to the seat plate on your model.

Work slowly and avoid prying between the base and the cylinder with a screwdriver.

How do you remove the cylinder from the seat plate?

Unscrew or unclip the seat plate from the cylinder, depending on your chair. On many models the cylinder pushes into a socket on the seat plate, and the removal tool or a mallet frees it the same way as the base side.

Turn the seat plate over and look for bolts or a mounting bracket. Remove those first, then separate the plate from the cylinder.

If the cylinder is pressed into the plate, tap it out from the plate side with the tool.

Keep the seat plate and its bolts together so you don't lose them. If your chair has a separate height lever or cable, note how it connects before you pull the plate away.

How do you fit the new cylinder?

Press the new cylinder into the base first, then set the seat plate on top and bolt it down. Line the cylinder up straight so the height adjustment works smoothly.

1. Stand the base on the floor with the socket facing up.
2. Push the narrow end of the new cylinder into the base socket.
3. Give it a firm press or a light tap with the mallet until it seats.
4. Set the seat plate over the top of the cylinder and press it down.
5. Refit the seat plate bolts and tighten them.
6. Turn the chair upright and test the height lever.

Check that the cylinder sits straight in the base before you add the seat. A tilted cylinder makes the chair lean and can wear the socket.

If the fit feels loose, stop and check the shaft and column sizes against your old cylinder.

Which cylinder fits your chair?

Measure the old cylinder before you buy. The two numbers that matter are the piston shaft diameter and the column diameter.

A common industry size is a 1-1/8 inch (28 mm) shaft and a 2 inch (50 mm) column.

The Office Oasis cylinder is a Class 4 gas lift, which the brand says is the most durable rating for these parts. Its kit suits readers who want the tool and the part in one box.

The Omyoffice cylinder offers a 5.5 inch adjustable range, with a fully expanded height of 16.9 inches and a minimum of 11.4 inches. It uses the same 50 mm column and 28 mm shaft.

Pick it if you want more lift travel than a standard cylinder gives.

The Rythalix cylinder is sized by rider height for a 3.9 inch travel range, and it's built for top-activated chairs. It doesn't fit side-activated models such as the Steelcase Leap series or post-2013 Herman Miller Aeron Remastered.

Check your chair's activation type before ordering.

How do you test the new cylinder and adjust the height?

Sit in the chair and run the height lever through its full range. The seat should rise when you lift the lever and hold when you let go.

If it sinks straight away, the cylinder isn't seated or the lever isn't engaging.

Press down firmly on the seat to check the hold. Then lift the lever and let the seat rise to the top, and lower it again.

A new cylinder can feel stiff at first, so cycle it a few times before you decide it's faulty.

If the height still drifts, check the seat plate bolts and the lever connection. A loose lever can stop the cylinder from locking even when the part is fine.

For a chair that wobbles as well as sinks, see how to fix a wobbly office chair.

What else should you check while the chair is apart?

Inspect the base, casters, and seat plate for wear before you put the chair back together. It's the easiest moment to fix other small problems.

Look for cracks in the base, especially around the cylinder socket, because a cracked base won't hold a new cylinder safely.

Check the casters for flat spots or hair wrapped around the axles; our guide to how to replace office chair wheels covers the swap. Wipe down the seat and base while they're off, and our guide to how to clean an office chair has the fabric and mesh steps.

If the seat feels hard after the repair, see how to make an office chair more comfortable for low-cost changes that don't affect the cylinder.

How do you dispose of the old cylinder safely?

Take the old cylinder to a local recycling or household waste site rather than putting it in the trash. Gas cylinders contain pressurized parts and steel, so they don't belong in curbside bins.

Don't try to open or cut the old cylinder to release the gas.

Once it's out of the chair, set it aside where it won't roll, and check with your local waste service for the right drop-off. Many areas accept them with scrap metal.

Keep the removal tool, though, because it fits most standard cylinders and stays useful for next time.

Which cylinder should you buy for your chair?

Buy the cylinder that matches your chair's shaft and column sizes, and pick a kit with a removal tool if the old part is stuck. For most standard chairs, The Office Oasis kit is the straightforward choice because it includes the tool and the part together.

Pick the Omyoffice cylinder if you want more height travel, and the Rythalix cylinder only if your chair is top-activated and you want height-matched sizing.

Before you start, measure the old cylinder, confirm your chair's activation type, and clear a flat work area. Then follow the steps above: separate the base, free the old cylinder, press in the new one, and test the height lever.

A 20-minute job can add years to a chair that still feels good everywhere else.

Frequently asked questions

Do I need a special tool to remove an office chair cylinder?

Not always, but a cylinder removal tool makes it much easier. Many chairs press the cylinder in tightly, so a purpose-built tool plus a rubber mallet saves time and avoids damaging the base or seat plate.

How do I know which cylinder size to buy?

Check the shaft and column diameters on your old cylinder. A common fit is a 1-1/8 inch (28 mm) piston shaft and a 2 inch (50 mm) column, so measure yours before ordering.

Can I replace the cylinder without taking the chair apart?

Mostly yes. You separate the base from the cylinder and the cylinder from the seat plate, but you don't need to dismantle the backrest or arms.

Flip the chair over and work from the bottom.

How long does it take to replace a gas cylinder?

Plan on about 20 to 40 minutes for a typical office chair. The slow parts are freeing a stuck cylinder and lining the new one up straight, not the actual fitting.

Why does my chair keep sinking after I replaced the cylinder?

A sinking chair usually means the cylinder is worn or the wrong size for the seat plate. Check that the shaft and column fit properly and that the cylinder is fully seated before you blame the new part.

Is it safe to replace the cylinder myself?

Yes, for most standard office chairs. Work on a flat surface, wear the gloves that come with a kit, and don't force a pressurized cylinder open.

If the base looks cracked or the chair is unstable, replace the whole chair.