Are all O-Rings Created Equal?

   / Are all O-Rings Created Equal? #1  

Gale Hawkins

Super Star Member
Sep 20, 2009
Murray, KY
1948 Allis Chambers Model B 1976 265 MF / 1983 JD 310B Backhoe / 1966 Ford 3000 Diesel / 1980 3600 Diesel
The major oil leak on the side of the transmission housing of our JD 310B BH was due to a dried out O-Ring. It occurred the first time I used the new thumb but I do not think it was related.

Did not make it to NAPA before they closed and did not try the other guys since I need other lines and seals too so I can get those future failure points address while I am under it greasy and the tools spread out.

My question are there different grades/qualities of O-Rings like there are for belt and hoses?
   / Are all O-Rings Created Equal? #2  
Im positive there is a difference in the ones you might get @ napa versus the junk stores like autozone, advance auto, and oriellys.
   / Are all O-Rings Created Equal? #3  
No, All O-rings are not equal.. Oh Yes! There are many differences.If you want to really get confused go to
google "parker o-rings" and bring up the catalog. Materials, fluids uses will stagger the imagination.
   / Are all O-Rings Created Equal? #4  
The O ring on my kegarator for the tap is still as good as the day I bought it 14 years ago. All others pale in comparison. Just saying:D
   / Are all O-Rings Created Equal? #5  
I often deal with o-rings that could barely fit around your pinky finger that cost $400 or more. So yes there is a wide range of o-rings depending on what chemicals the are going to be exposed to, static seal vs dynamic, elasticity, heat ranges, and more.

Even the basic Viton o-rings come in different varieties. Lately we've been seeing some plastics that work very well and are cheap entering the market. My guess is in 5 to 10 years you'll see them take over for the generic Viton and Buna o-rings.

As far as what you'll get at the local parts store, it's anyone's guess. But it'll probably last as long as the original o-ring.
   / Are all O-Rings Created Equal?
  • Thread Starter
#6 5700 Parker_O-Ring_Handbook.pdf

I see what some of you are saying. The Parker info shows the differences are many.

First I will start with NAPA and tell them the application and judge the info.

What bites it looks like someone had removed this main valve body feeding both the hoe and FEL circuits that boths directly to the transmission case before and replaced one of the two. One looks new like and the other one now is very undersize, pale in color and broken. The valve body is held on by three bolts and only two look OEM.

I will replace both while there as well as the hose to the hoe since the wire layers are already loose and snagging on roots, etc.

The BH is 29 years old and still has a lot of the OEM hoses it seems.
   / Are all O-Rings Created Equal? #7  
Are all O-Rings Created Equal?

A lot of attention was focused on O-rings in the wake of the last flight of the Space Shuttle Challenger. Seal design and material selection depends on what type of fluids you are trying to seal and in what environments. Parker publishes what I consider to be the O-ring gospel:
   / Are all O-Rings Created Equal? #8  
I got a couple sets of o-rings from HF. They seem to last pretty well.
   / Are all O-Rings Created Equal? #9  
I can say from experience with my solar heating system that O rings are not all equal. The standard buna O rings will swell up and soften when exposed to the synthetic oil used as a heat transfer liquid. Viton works fine, but some gaskets, like the ones that came with circulator pump flanges, must be buna, because they have to be replaced with whatever comes close in viton. My biggest problem is with the expansion tank- the bladder material is not compatible, and I can't find viton bladdered tanks like the original ones from the late 70's. Always something.
   / Are all O-Rings Created Equal? #10  
"O" rings are a bottomless pit of innovations and improvement. I worked on Class eights, and never threw out any "O" rings they all have different characteristics and uses some are made to swell. Cat was a great source.
When in doubt get the right one, and pay the extra dollars, that is the best chance you do not have to do the job multiple times.