sorry forgot to link the image that I was referring too, have a look at it in the first reply and I think it will help you understand the parts in question.
I think those parts are probably either broken by now, or some of them missing in the first place, if the metal washer are actually missing that mean the seller just sold you something that they broke, as for fixing it, you would basically need new set of those parts, for example like this.
Could be bearings from the mechanism that holds the gas cylinder.
Due to its brand, it may be OEM but this popped up when I googled rolling chair replacement O rings:
Replacement Hardware Repair Kit for Office Chair Gas Lift Cylinder - S4451-K https://www.amazon.ca/dp/B00CEZ1EOK/ref=cm_sw_r_apan_glt_i_VZYQRYFPBVHWDDKF3E4Y?_encoding=UTF8&psc=1
If it is indeed non-standard size, try heading over to a 3D printing sub. Pose the question and provide your measurements, they may have some wizard calculate the density and appropriate size they may print for you (for a $ of course). I think there are guys on eBay who would support this too.
I've had this happen to me before actually. You can either replace the whole cylinder or buy these to replace the hardware actually inside the cylinder (this thing you're holding being the bearing that exploded). A more temporary solution but cheaper and easier, so up to you!
Note the DXRACER official response below and don't void your warranty, that being said.
The video helped me disassemble the chair however just adding grease did not resolve the issue. In the video the rubber grommet is in the wrong place during installation and what isn't shown is that there is a 2nd washer missing, likely at the bottom of the wheel portion. The bearings need to be sandwiched in between 2 metal washers and that is missing in the video.
This part sold though amazon resolved my issue. Follow the instructions that come with the repair kit exactly and it will resolve that popping and clicking issue. If you look at the reviews look at the customer images. the image with the 4 parts is the issue that is happening with your chair.
Part URL: https://www.amazon.com/gp/product/B00CEZ1EOK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
Hey man I fixed my DX Racer's clicking noise by replacing the bearing and washers. My washers had dents in them from where the bearing sat and was causing some looseness in the assembly. Cost me 9 bucks on amazon.
/u/DXRacer this is a very common issue on many of your chairs. Why do you guys give the people the run around? Send them a rubber washer, 3 metal washers, a bearing, and a retaining clip and call it a day.
I think its the piston thats broken. https://www.amazon.com/Replacement-Hardware-Repair-Office-Cylinder/dp/B00CEZ1EOK this should help or just repalce the whole piston.
Here is the Finished product I put the washers as well as the broken circle washer with metal balls at the end of the metal cylinder where it fit perfectly and due to the base of hollow tube the washers have stopped the metal cylinder from poking through. They must have fallen out when moving good thing I saved them not knowing then they were a part of my chair. I plan on milking this old chair I got from Craigslist for $200. Hopefully this helps someone else like me with a similar problem. EDIT: I found a replacement on amazon that solves my problem https://www.amazon.com/Replacement-Hardware-Repair-Office-Cylinder/dp/B00CEZ1EOK/ref=sr_1_16?dchild=1&keywords=herman+miller+aeron+replacement+parts&qid=1595146550&sr=8-16
You can get the kit for $10 on Amazon https://www.amazon.com/Replacement-Hardware-Repair-Office-Cylinder/dp/B00CEZ1EOK or a new cylinder for less than than $20 https://www.amazon.com/Rolland-Office-Chair-Lift-Cylinder/dp/B011HCQUZ8/ref=sr_1_1?dchild=1&keywords=chair+cylinder+rolland&qid=1587840564&s=home-garden&sr=1-1.
Can't see the photo linked currently, but if the metal post is sticking out the hole in the caster base then you can get a $10 repair kit for it. This happened to mine a few years ago and I bought this one from Amazon.
Also here with a diagram/video.
No I do not.
I actually miss my mesh chair now. I'm not gonna tell you not to buy it but here is my experience.
I have a King DX Racer. I wanted a larger chair since I just like them bigger. This is supportive up to 300 lbs I believe and I am nowhere near that. 5'11 and around 200 lb's so well within the 'range'
Most people within a 6 month period get the chair squeak from hell. You will need to than call the cs and get a new hardware kit or buy one off amazon. Seems strange so many people have this issue within the 1 year period but you can google it. Pretty common. Also I have had mine replaced for about 3'ish months and its already making sounds again, which means I will have to replace it again soon.
This chair is so ungodly hot. NO BREATHABILITY. I think there is a fabric version but of course thats not popular so good luck finding it. I do not live in a sauna but wow especially in warm months this chair feels like I am in one. Now that its winter its like having a warm fire on my back. So if you live in Antartica this chair is probably amazing.
Its not that comfortable. Chairs take time to break in but I am almost a year into this chair and its still hard as rock. I guess that is good and bad.. I mean a mushy chair in a year sucks too but I wish this was a bit more comfortable.
On the plus side, It has a high back which is one thing I required and most office chairs don't go this route or are super expensive. It has good customizability. Can really control how the back sits or the angles. Still not comfortable. (maybe it takes 3-6 years and I will love it?)
It looks great which is why so many people buy it. Who doesnt want a formula 1 driving seat to sit in.
Maybe I sound over critical and the price isn't awful.. I have also priced 'real' office chairs and I know how much they cost. $500 is the average low to mid end so I get it. I am just overly disappointed and kind of wish I had spent a bit more money for the one that isn't on every twitch gamer stream. If you can try one in person somewhere I would and maybe see if there is a fabric version if you can stand it. Like I said I miss my mesh chair now.. was so cool.
I am just stuck with this because like you said.. who wants to buy some guys old chair. That fart line made me lulz.