Hydraulic fittings; JIC or O-Ring Boss?

Delta KJ - The o-ring fittings are a superior arrangement that provides a higher level of sealing ability .. lower damage susceptibility to variations in torque levels .. and higher levels of re-useability involving frequent connection and disconnection.
It goes without saying that the JIC fittings are cheaper to manufacture and purchase. JIC fittings are weight-saving where less weight is highly desirable.
My personal choice would be the o-ring fittings. Here's a good hydraulics website with a lot of useful technical information ..

http://www.kurthydraulics.com/threads.php

I am not a fan of some of those "O" ring boss" fittings, especially the ones that use a jam nut and washer as back up and use them only where I have to. I also find the variety of JIC fittings to be more extensive. I make all my own hoses and buy my fittings from www.discounthydraulichose.com they have been an excellent source and I have had no problems even though the bulk of the materials are made in China.

The biggest single problem I've had with JIC fittings is the nut splitting after regular hose changes. Maybe it had a lot to do with the particular brand, and some brands are better than others .. but I always used Aeroquip fittings, and usually had a good run out of them.
The o-ring fittings require care with regard to making sure that o-ring seating areas aren't damaged or dirty .. and that you use top quality nitrile o-rings. The JIC fittings are somewhat more accommodating of mismatch and poor fit, or damage to the beveled surfaces.

Speaking of nut splitting....that is a real problem with the pipe thread swivel nut fittings and I definitely would not recommend using any of them (although I have used a few) I have not had any problem with JIC nuts...even the China sourced units....but there are limits to how much torque any of them will handle.
I also put the thread joints together with never seize as they can become rust welded together and a problem to take apart.

I think you guys have o-ring boss and o-ring face seal fitting's confused?
Good luck Bob

I think you guys have o-ring boss and o-ring face seal fitting's confused?
Good luck Bob

Blueox I was thinking the same thing.



Most Hydraulic systems that use JIC fittings, also use O-ring boss fittings. So there isn't really a difference as far as pressure goes if that's what you are asking. The difference in use is primarily ease of manufacturing. O-ring boss is typically used in housings as it is easier to machine than trying to get a taper at the bottom of a threaded hole, and JIC was typically used for tube ends. What you want to avoid in higher pressure applications are pipe fittings.

This is what the D6D SA used in their construction.

The Yellow fittings came off the toolbar connection block (1P3600) that is mounted on the fender right in front of the cab. The tool pictured is a porting tool used to create a -8 O-Ring boss port.


Sounds like you are closer to getting that D6 ready to do some laser grading.

I started to do some laser work on Thursday after taking the rest of the week off of work to fix some problems on some of the family's ground that has been in permanent beds for the past decade. First thing I noticed the scraper wasn't cutting level after 3 - 4 loads from the top corner, hauling 1/3 mile down to the middle ditch where the drain left a big divot. Sure enough blew a tire. They weren't able to get to it Friday, well see how it goes.

Not sure if anyone is interested, but if you are in the middle of ORB - JIC plumbing job JIC & ORB have the same thread pitch & alot of the fittings are inter-changable just by adding an o-ring & filing off the JIC taper.

This info. has got me out of a few binds when your not close to a parts store.