How close is "close enough" for hydraulic O-rings?

[gw@swmo]

I just received a new Boss 27-ton log splitter from Costco. When Costco assembled my unit, they left out a rubber O-ring where a hydraulic hose attaches to the oil reservoir. Costco is trying to contact Boss to obtain a replacement, but they are not answering their phone. The email I sent to Boss was returned as undeliverable, and for the past two days, I can't get their webpage to load. So I may need to get the O-ring elsewhere.

The missing O-ring is described as 15mm x 1.9; it's outer diameter is 15mm and the rubber material is 1.9mm in cross section, so the inner diameter is 11.2mm. So far, I have not been able to locate this exact size online from any US source. But there are plenty of online sources selling nitrile O-rings which are 15mm OD x 11mm ID x 2.0mm cross section. Is it unrealistic to think the extra 0.1mm in cross section might still work?

There is another souce in the US selling an O-ring with the correct 1.9mm cross section, but ID of 11mm and therefore OD of 14.8mm. So the O-ring would have to stretch 0.2mm in diameter. Close enough, or not?

I have found a source of the correct size from Hong Kong, so maybe that is my best option?

 

[salecker]

Find a Oring kit from locktite and make your own

 

[gw@swmo]

Find a Oring kit from locktite and make your own

Thanks for the suggestion. That O-ring kit looks like an interesting idea which might be really helpful in some situations.

However, the smallest cross section rubber in the kit is 3/32" which I believe converts to 2.4mm, where I need 1.9mm. I think I might be able to fudge a little bit on the diameter of the O-ring, but I'd like to keep the cross section as close to specifications as possible.

 

[Pinesmoke]

For a no pressure connection it should be fine, I assume it's the return line to the tank. If you are running normal hyd oil there is no need for nitrile, buna will be good.

Poke around, I would think there will be a hydraulic store close to you. You can check McMaster.com if all else fails, they have anything you could need.

WARNING
Mcmaster-carr is a black hole of aallllll kinds of goodies and can suck you in. 😂

 

[gw@swmo]

For a no pressure connection it should be fine, I assume it's the return line to the tank. If you are running normal hyd oil there is no need for nitrile, buna will be good.

Poke around, I would think there will be a hydraulic store close to you. You can check McMaster.com if all else fails, they have anything you could need.

WARNING
Mcmaster-carr is a black hole of aallllll kinds of goodies and can suck you in. 😂

The fitting is of the O-Ring Face Seal type, and it is for a hose described as the "oil return hose."

No doubt, McMaster-Carr is an awesome resource! So when I discovered they do not carry the exact size I need, I knew I was looking for something out of the ordinary.

McMaster-Carr does have several offerings with 15mm OD, but with a cross section of 2.0mm. I'm guessing that's close enough to 1.9mm, but I don't really know, which is why I'm asking.

Thanks for the tip about looking for a hydraulic store. I found two in my home town which I will try to contact tomorrow.

 

[Turbo89]

The fitting is of the O-Ring Face Seal type, and it is for a hose described as the "oil return hose."

No doubt, McMaster-Carr is an awesome resource! So when I discovered they do not carry the exact size I need, I knew I was looking for something out of the ordinary.

McMaster-Carr does have several offerings with 15mm OD, but with a cross section of 2.0mm. I'm guessing that's close enough to 1.9mm, but I don't really know, which is why I'm asking.

Thanks for the tip about looking for a hydraulic store. I found two in my home town which I will try to contact tomorrow.

If you know the fitting p/n, the Parker fitting manual has really good guidance on o-ring fits.

Generally speaking, bigger is better… it it’s too big it’ll get cut at assembly. Since it’s a face seal, that small of difference probably won’t be noticeable. Put some o-ring lube on it at assembly, if you don’t have any use oil or Vaseline.

If you post up the fitting p/ns and manufacturers, I’ll dig through my old Parker books and see if I can find the allowable o-ring tolerances, next week when I’m back in the office.