How to fix an office chair

Updated June 2026Independently researchedNo paid placement.

Why does my office chair keep sinking?

The seat drop almost always comes from the gas cylinder, the pneumatic lift that holds your chair’s height. Inside is a piston and a sealed chamber of compressed gas; over time the seals wear out, gas leaks, and the cylinder can no longer resist your body weight. The chair will slowly sink or suddenly drop when you sit down. If the cylinder is truly worn, there is no magic fix that restores the gas pressure. You can buy a replacement cylinder that matches the taper and length of the original, or you can use a mechanical shim or clamp to physically stop the seat from descending. A shim is a quick, low-cost workaround, but it trades away easy height adjustment. Replacing the cylinder keeps the chair fully adjustable and is the more durable repair.

How to fix a sinking office chair gas cylinder

First, flip the chair upside down on a soft surface. Most seat plates attach to the cylinder with a large circlip or a bolt; remove the bottom cover to see how your chair is put together. Tap the old cylinder out with a mallet or a block of wood, then insert the replacement so the taper matches the seat plate and the base. Make sure the new lift is the correct length and stroke for your chair’s height range. If you don’t want to replace the cylinder, a cylinder shim or a heavy-duty hose clamp around the shaft can stop the sinking. These work by increasing friction on the piston rod, but they may limit adjustment and can damage the cylinder if over-tightened. For a cheap or older chair, a shim is a reasonable temporary fix; for a good chair you plan to keep, spend a little more on a proper replacement cylinder.

How do I stop my office chair from squeaking?

Squeaks usually come from metal-on-metal or plastic-on-plastic rubbing at the swivel, the tilt mechanism, or the armrest attachments. The first step is to tighten every bolt and screw on the chair, because a loose joint will squeak and wobble. A hex wrench or screwdriver is usually all you need. For the moving parts themselves, use a dry lubricant like silicone spray or a PTFE-based grease. Avoid WD-40’s standard formula as a long-term fix because it evaporates and can attract dust; a dedicated dry lubricant lasts much longer. Spray the gas cylinder shaft, the tilt spring pivot, and the base under the seat, then move the chair through its full range of motion. If a squeak stays in one armrest, remove the arm and apply a thin layer of grease to the contact surfaces before reinstalling.

How do I tighten a wobbly office chair armrest?

Wobbly armrests are almost always caused by loose bolts under the arm pad or where the arm attaches to the seat frame. Lift the armrest pad; you’ll usually find two or four bolts recessed in holes. Use the correct hex key or Phillips screwdriver and turn clockwise until snug, but do not torque so hard that you strip the threads. If the bolts keep loosening, apply a small drop of thread-locker to the threads and retighten. In some cases the armrest mount is a plastic bracket that has cracked or the screw holes are stripped; then the honest answer is to replace the armrest set or order a matching part from the manufacturer. Check whether your chair’s armrests are adjustable in height; the locking mechanism itself can wear out and may need its own repair or replacement.

Can I replace the casters on my office chair?

Yes, casters are one of the easiest parts to swap. Most office chairs use a standard stem size, either a round tube or a grip-ring pin, so replacement wheels from a hardware store or online seller will usually pop straight into the base. If a caster is cracked, dragging, or leaving marks on your floor, replacing it is a five-minute job. Match the replacement to your floor type. Hard plastic casters are fine on carpet, while soft rubber or polyurethane casters protect hardwood and tile from scuffs. If your base has hooded or dual-wheel casters, measure the stem diameter with a ruler before ordering. Worn casters can also make the chair feel higher or lower than intended, so fixing them restores a smooth, stable rolling motion.

When is it better to buy a new office chair instead of repairing it?

That depends on the chair’s build quality and how many things are failing. If the gas cylinder, casters, and armrests are all worn out on a budget chair that you’ve had for years, replacement is often the sensible route. The labor and parts cost can approach the price of a new budget-friendly model, and a used chair with multiple failures is unlikely to feel solid again. On the other hand, a well-made ergonomic chair with a strong frame and a good warranty is worth repairing. Replacement cylinders and casters are commonly available, and the fix can give you several more years of comfort. Look for a manufacturer that sells spare parts; if they don’t, and the chair is out of warranty, weigh the cost of a generic repair against the price of a new chair with the features you need.

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