My New Holland tractor has hydraulic fittings that keep destroying o-rings.
They are straight male thread with a jam nut that tightens up the o-ring.
Like this;
https://www.agrisupply.com/1-2-male...msclkid=a648cd7d9b571d662c68ac7f51cbe67d

The other end of the fitting is JIC.

II have worked with these in the past, and really didn’t have a problem with blowing o-rings.
Whenever I removed one of these fittings I would always screw them in till the o-ring seats on the fitting and the threaded port matched up making an even V.

There’s one fitting, the rod end of the loader boom/arm cylinder that’s mostly the problem.
Is there something that’s wrong with my setup method that would cause premature o-ring failure?
I guess I could go shopping for and o-ring with a larger thickness to take up more room under the jam washer.

can you ask the local dealer's shop foreman about it?

Might screw them down some more then tighten the jam nut.

I believe that it will last longer.

That sounds odd. I try to keep the Oring sort of centered, away from either threaded part but I don't know that it's critical. I don't think I've ever blown such an Oring. Never changed an Oring only, but I have had bad fittings that would have tiny leaks. (Used parts)

I'd look closely at the cylinder where it threads in. If you don't see a flaw there try a different brand of fitting.

I personally wouldn't try a different size Oring, I think that's just asking for a leak.

Just my .02.

+1

http://blog.parker.com/turn-vs-torq...-hydraulic-fitting-connections-leak-free

Some fittings need to be torqued. Some don’t.

On the rod end? Not the gland end?

Hmmm....rubber hose to the fitting or steel?

No chance something is getting torqued out of shape is there?

ORB system...it's O-ring boss, you are probably using O-rings from a standard "dash size" kit...no, no don't do that...buy a kit from on-line or any hyd dealer...SPECIFICALLY the ORB O-rings which usually have a higher durometer and smaller cross section diameter which is designed to exactly fit in the chamfer of the female port. When re-installing the fitting, insure that when the jam nut is tightened the new O-ring is centered in the smooth portion of the fitting. The jam washer and smooth portion of the fitting and the chamfer should be free of obvious nicks and grooves.Forget torque and rocket science, just tighten the goddam thing up with a crescent wrench or whatever is rattling around in your machines tool box. 55 years in the trade.

I own a hydraulic shop. What O-rings are you using? The fitting in the pic is O-Ring Boss thread, the port it threads into will have a recess for the o-ring. If that is what you are using it takes an SAE O-ring Boss BUNA O-ring, just any old o-ring will not work and will fail. Any hydraulic shop will have o-ring kits for ORB fittings (they come in standard sizes) and many will just give you an o-ring or two, at least that is what we do in our shop.

That is an ORB - oring boss- fitting. The orings are a specific size for that Fitting. You can find the oring aftermarket but it won’t be at Lowe’s or Home Depot.

Oil the oring to begin with.
The correct installation is run the jam nut all the way back. Thread the fitting Until the oring touches, if the fitting is not oriented correctly, turn the fitting CCW up to one turn to orient as needed.

Tighten the jam nut using a back up wrench to keep from twisting the oring. If it still leaks, check the area in the cylinder where the oring sits.

This! Squirrelnut knows what he is talking about!

I have only used NH parts so far, and yes I am aware of correct o-ring material for the system.

Thanks for the assembly procedure, I probably need to screw the fitting in more, I don’t recall screwing it in that far.
I have looked at all port and fitting surfaces with a magnifying glass. Everything looks fine, no cracks or rough spots.
I can’t tell you how many of these fittings I replaced when I was working and never had a problem with that O ring boss end, it was always the tapered ends. Gorillas can deform them a surprising amount.