sleeve "O" rings

be careful, sleeve orings are sometimes made of different material, but for a play tractor, you'll probably never know the difference. 

I bought a set from the agco dealer a couple weeks ago. 4.37 a piece.

Thinking that hydraulic O rings are not as good as what you would buy from AGCO would be to not know much about hydraulics and not thinking. I have removed O rings from hydraulic valves that have held oil from leaking for over 20 years with the press running 24 hours a day 5 days a week or more under 2000 pounds of spiking pressure.

Ours are 2.50 each.  That basically covers the time for me to run to my supplier in Tulsa and pick them up.  It also covers the initial research I did to find the right size since the ones I removed were so damaged.  It took a few tries.  Ours are Buna, usually 70 durometer but ocassionally 90 since it's tough to get the suppliers to carry 8 at a time for some reason.  When they have them, I buy 40 at a time.

Edited by JimD - 31 Aug 2010 at 8:55am

300 percent markup is acceptable?

As a retailer I have to agree that the markup on small items may seem high, but when you consider the cost of filling a $20 order you will eat up most if not all of any margin you could put on a small item with overhead costs.

Put another way, I often get chastized for having a 25 cents per bushel margin on corn. So a customer brings in a couple of barrels to get corn, 10 bushels, the total sales margin is $2.50. The labor cost to fill that order is about $5.00, ticket processing is at least $5.00 and my cost to store, elevate and OH cost are around 20 cents per bushel. Did I make any money? Probably not. My only hope is that the customer will buy some higher margined products so I will be here next time they need a couple of barrels of corn.

Edited by John (C-IL) - 31 Aug 2010 at 9:27am

Spend some money with us, and I might just toss one in too!  But to stand in the peanut gallery and complain that we are overcharging won't fly.

There is no way - no EFFIN WAY, I'd ever use Buna-N for a coolant application - especially when I have one chance and one chance only to get it right.

The whole point of replacing parts is to "get it right".

The price/markup means nothing to me.  A seller has the right to charge what he wants - and I have the right not to pay it.

Buna-N is NOT the right material for wet sleeves and I will gladly pay whatever the going rate is for an approved product.

That said, I respect Dick L's experience - that carries some weight with me.

But I ain't taking the risk.

There are many good references for suitability of material for 0-rings, depending on  fluid/gasses they are exposed to. None of them name Buna-N for the common engine coolants. They do variously name HNBR, Flourocarbon or EPDM.

I have no idea which of those materials were around when A/C designed these motors. But until a better authority presents itself, I'm going to use "Factory" at that location.

JimD wrote: OK, what material do you recommend?  Since I explained the application to my salesman, and he recommended the material. I also had in-hand the original, and some new AGCO rings to compare.  It's also possible I'm wrong on what they sell me since I've been buying them for so many years.  I just walk in and they hand me whatever stock they have on the shelf.  They just keep them in stock for me.  I'll have to check my reciept to see what it is. I just remember for sure the durometer #'s because the 70's have been in shorter supply lately, and the 90 are a little harder to install.   Now you have me worried, though I've never had a customer complain of leaking, only that I stuck the wrong ones in the bag.

Well Jim, I am NOT trying to come off like a know-it-all. What I am is "done it all wrong once" guy who can't afford eff-ups.

http://www.manuf-rubber.com/
http://www.manuf-rubber.com/pdf/Material%20Guide.pdf

That's just one source, and it is NOT a recommendation.

I fully understand that the old A/C and other old brands are very forgiving - more to their credit. I just can't see risking a $2000 build over 40 bucks worth of o-rings.

That 70 durometer - heck it may even be high for a 1940-1950 era design - but I don't know.

I also know these things have shelf life, and wonder how many NOS o-rings are being used and if they contribute to more frequent sleeve leaks. Those leaks come up frequently in other forums, both antique and modern engines.

Leave o-rings open around any place where electricity is being moved  - generators, welding shops and so on - and the ozone will affect any of the neoprene based products - it's the same thing that breaks down the sidewall rubber on tires.

Heck, I'll try a non-specced o-ring almost any other location to get something going, but NOT THERE!

When I was a kid, doing my first engines, I revered a guy who owned Joe's Industrial - an engine shop in my area. He did all my sleeved Ponchos and Hemis. For me, his word was Law.

I don't know if there are any engine shops out there today that has the depth of experience and integrity to give you an informed answer - but that's where I'd start.

I'm lucky - we do our own machining, and have engineers to make the calls.

HNBR & 70 duro is a guess - but just a guess. The 602 Continentals and 844 LeRois I distinctly remember having a softer bottom 0-ring (softer than 70 duro) and copper at the tops.

Oh: HNBR stands for "Hydrogenated Nitrile" - very common in the aircraft field. LOL! - it won't blow up in oxygen!

301 service manual shows Buna-N for the top o-ring (in contact with the coolant) and a silicone one for the bottom (in contact with the oil I guess?).  It didn't have the hardness, but I would guess the buna were 70, since they were a little softer than the normal 90s I have around the shop and the silicone were even softer than that.  The service manual should give the material of the o-ring somewhere I would thing.

EPDM seems to be the material of choice these days for coolant hose but I am sure that stuff was not around back then and the old materials worked fine.   I was told horror stories of aftermarket sleeves that required odd seal ring sizes.  Maybe the Allis originals stayed consistent.

Rick of HopeIN wrote: EPDM seems to be the material of choice these days for coolant hose but I am sure that stuff was not around back then and the old materials worked fine.   I was told horror stories of aftermarket sleeves that required odd seal ring sizes.  Maybe the Allis originals stayed consistent.

Yes, EPDM is referenced everywhere, with FEPM starting to make a dent.

Buna-N is the first material I'd ever heard in regards o-rings. It's also the cheapest per piece. The A/C design goes back to what - the late 30s? So maybe that's all they had to work with? But what about hardness?

CAT's 3400 series was originally built using EPDM, but they had horrible leak problems, and eventually went to HNBR. On the big HP versions, they now use EPDM in the top groove, HNBR in the second, and Viton in the third.

Buna-N is working right at its temperature limit when used in a cylinder sleeve location, and HNBR has a comfortable 50% advantage - which means it lives longer.

Of the older engines I've worked on - those of the same era - my "recollection" is that the o-rings were softer than the ones on the shelf for hydraulic applications.

If I had to guess - maybe 50 duro.

When it comes to this particular O-ring application, I've got to go with what Allis Chalmers specced. (heh-heh - it probably IS el cheapo Buna-N).

i would bet the $5. rings form AGCO ar Buna N. 70 years ago that was your onlly choice. I still use them today. If your building at B-C- WD45 thats fine. IF your building a $10k race engine, maybe majic o-rings are needed. NOT for a factory build on a 50 HP motor that is 70 years old.

I have seen the 'will pass for the correct part' o-rings used, they don't conform as the stock units, they generally do not take to the mix of oil and antifreeze and they generally fail when you need them the most.  Stick with OEM, you will not regret it in the long run as stated earlier, why risk a major overhaul on going cheap on o-rings?

If this was me I'd feel I should have investigated options before I ordered product. I'd try to recognize the vendor was selling what I had ordered at an agreed-to price. It would be hard to blame him because I didn't look at other options before I placed the order. I'd look at $40 as a cheap lesson to consider other options in the future if I was so inclined.