Hi everyone,
I have several height-adjustable bar stools like the ones shown in the attached photos, and they have developed the same problem.
The stools use a lever underneath the seat to adjust the height. When I pull the lever without sitting on the stool, the seat rises normally and can be adjusted to its maximum height. However, once I sit on it, the mechanism does not seem able to hold the pressure/height anymore.
Under my weight, the seat gradually sinks until it reaches the lowest possible position. If I stand up and operate the lever again, it rises normally, but the same thing happens as soon as I sit down.
The stools are otherwise in good condition, so I would prefer to repair them rather than replace them.
From what I understand, these stools probably use a gas-lift/pneumatic cylinder similar to an office chair, but I have never disassembled this type of mechanism.
I would appreciate some advice on:
- Is this symptom usually caused by a worn or failed gas-lift cylinder?
- Could the adjustment lever or valve mechanism be keeping the cylinder slightly open instead?
- Is there any practical way to repair/recondition the existing cylinder, or is replacement normally the only solution?
- Are these cylinders generally standardized, or would I need to measure the existing one before ordering a replacement?
- What measurements/specifications should I check to find a compatible replacement?
- How difficult is it to remove the old cylinder from the base and seat mechanism without damaging the stool?
I have several identical stools, so if the cylinders are the problem, I would ideally like to repair all of them rather than replace the entire set.
Photos attached showing the stools, adjustment lever, base and central column.
Any advice on diagnosing the problem before I start taking them apart would be very helpful.
First thing is checking they’re rated for your weight. If they are, I think the problem is not a loss of pressure because I would’ve gone soft very fast in a couple up-downs. So imo (not a specialist in pneumatic things, but I’m pretty good with machines in general) it must be the valve you move with the lever not closing properly. I have a couple chairs at work that don’t have spring-loaded levers and you have to push down them for the chair to stay at the chosen height, so try pushing the lever a bit. If it’s an outside problem—something bent or badly adjusted, dirt or something that stops the movement of the mechanism— then you might be able to fix it, but if it’s an inside problem with the valve itself, it’s worn out or gets stuck, then I’m afraid you’ll have to replace the whole piston assembly.
To answer your questions, as I said I don’t have that much experience with pneumatic parts, but parts in general are never too standard nor very custom, that is they usually are standardised but there are so many standards and specifications and variations that yours may be hard to find. Look for references/codes printed on the cylinder, the specifications you’ll need to find another one would be diameter(s), length(s), displacement, pressure/force, there could be also different kind of fastening types and ways to actuate the valve.
How hard it’s going to be, I can’t tell, but it’s most likely possible to do.
Don’t disassemble any gas cylinders, but I know the cylinders in office chairs are adjustable. On an office chair there may be a knob on top of the cylinder you can rotate one way or the other. Check if that’s something you can try before going for something more expensive?
‘This only Tony’ disassembled one on YouTube a few years ago if you want to know what is inside. He didn’t try to get it working after and if he doesn’t have confidence in doing that, then you shouldn’t either. As others said the pressures are dangerous, higher than your normal air compressor so what his videos to see what is inside them throw it away. They are fairly cheap considering.
Whatever you do, DO NOT mess with the gas cylinder, that could explode and cause you a lot of hurt, even death.
Quick question: are these chairs designed for your weight?
Stop calling them a lard ass, rude.
There is no fixing a broken cylinder like that unless you’re an expert and you know what you’re doing. Please don’t attempt to disassemble, puncture, drill, or cut the gas-cylinder itself.
The best way would be to get yourself a proper gas-cylinder removal tool, and watch some YouTube on how to use it and replace the gas-cylinder entirely.
I would suggest you just buy one replacement (you’re going to have to take it apart and see what you need) and then if everything works out then you can buy more.
It’s a little weird it’s all of them not just one or two, so maybe someone has a better idea, but the symptoms sound like it’s a gas cylinder problem. Afaik they sometimes get a little dust and dirt in the seals and don’t seal off proper any more. But since it’s all of them the gas cylinders might just be cheap or not suited for the task.
I don’t know if you can repair the cylinders themselves, I’d be
a littlea lotta careful, since those are built to handle some weight they can be under a fair amount of pressure. So disassembling one of the cylindersmightwill be dangerous, if you don’t know what you’re doingThere are several different sizes of those cylinders, so you’d need to measure one of them before ordering. I’d just look up what measurements are listed for those cylinders online and then disassemble one stool and take the same measurements. Other than that they should be replaceable fairly easy.
That’s the knowledge I accuired online when my beloved office chair started to develop the same issue, but since it still functions most of the time I never got around to actually disassemble it, so take everything I said with a grain of salt and maybe get a second opinion. Good luck!
edit: after looking at the other comment I emphasized the dangers those cylinders can inherit, I still think that replacing them will be fairly easy since the replacement parts are offered online alongside instructions how to
Disassembly is quite dangerous and can be lethal.
Cue video of the guy getting a surprise vaginoplasty from an office chair.
hmm, do i want to know?
So disassembling one of the cylinders might be dangerous.
This. If I were you I’d set one to the height I wanted and then shim it. With that “upside down” style it’d hold tight, but you’d lose the air cushion.
