Hydraulic fitting type / size for grapple

Tomahawk3830 · Jun 22, 2020

I have a Kubota L3830 4wd HST with dealer-installed rear remotes. Rear remotes have two female ISO 5675 connectors. I have a 66" CID grapple with one cylinder. The grapple has flat-faced ISO16028 connectors (one male, one female). I want to run the grapple off of the rear hydraulics. The grapple uses hoses marked with ISO11237-1/EN857/2SC/6,3 11-4Q17 marked on the hoses. I've not previously worked with hydraulic hoses so I'm educating myself as I go. My hoses will need to be 210" long to allow for sufficient slack with loader movement considered. I confirmed that I can mount the tractor flat face connectors on the front cross member of the loader and the grapple hoses will be long enough even at full curl with grapple closed. I work at a place who has a hydraulic hose crimper so I can likely get what I made for cost of parts but I'm open to buying off-the-shelf components if that makes more sense.

Hoping someone can answer the following...

1. From the "-4" on the grapple hose, I assume that is a -4 or 1/4" hose. Any reason (i.e. reduce pressure drop) to run 3/8" hose from the rear remote to front connectors or should I stay with 1/4" to match what is on the grapple? I only plan to use the grapple as the only attachment that would need hydraulics on the FEL. I assume I'd want a "2 wire" hose?

2. I see there are NPT, JIC, ORB and other seal types on the fittings. Which is best?

3. The "rear" of my hoses will both need ISO5675 male connectors to plug into my tractor's rear hydraulics. I would prefer to have a 90 degree fitting right near the connector to minimize the amount the hose loops around in the 3pt area. Can I simply buy a threaded 90 and assemble or do they make ISO5675 male connectors with a 90 already in place?

4. I have access to metal fab equipment and I have my own welder so I can make a bracket to "rigidly" mount the front flat face connectors to the FEL cross member hole guard. I was surprised that I cannot find a bracket or mount for twin ISO16028 flat face connectors (one male, one female) - does anyone know where I could buy one? If not, is there a typical way that these mounts would work? I see some factory brackets have "double humps" that sandwich the connectors between the two halves of the brackets. Other factory brackets seem to be made from flat stock with holes for the connectors and simply have the fitting go through the bracket and use some sort of "lock nut" to tighten the fitting to the bracket - if I have to made one, I'd prefer this type. Are there flat face connectors that have this extra locking nut to tighten the connection through a bracket? I've not see any.

5. If I ended up making hoses at work I will probably simply make them one pc hoses 210" long. I've also been looking for perhaps a 10' and an 8' premade hose and adding quick disconnects between the 10' and the 8' to allow for easy removal of my loader. What is a good source for standard length hoses?

Thanks in advance for your input.

Industrial Toys · Jun 22, 2020

I don't like JIC since it is said you can damage them if over tightened. NPT is true and trusted but kind of primitive. ORB is nice because you can have the angle you wish because tightness of the main fitting is not an issue as with NPT.

The fittings you want I would guess are called bulk head mount.

I have dozens of flat face "tool" couplers and really hate them for not being able to connector or disconnect under the slightest pressure.

I made the flat face couplings on the front of my loader have short tubing that are mounted in a block and are sacraficial. I have ripped them off a few times and only had to replace the four inch or so NPT tubing which I keep in stock..

As for size. You could go very small. It is not very critical. I think my grapple has 3/8" hose but I'm sure 1/4" would work just as well.

KWentling · Jun 23, 2020

JIC is my preferred fittings for hydraulics. Yes you can damage them by over tightening. Small JICs like these would be tightened finger tight and then one flat on the hex. A little more if it leaks. Use bulkhead adapter fittings on the flat face couplings. I know of no coupling with a built in 90, so use elbows there. ORB fittings are good too for the same reason JIC are good. NPT fittings are very commonly used but not the best by far. 1/4" hose is probably fine. 3/8" might be better because of the long run but probably not necessary.

ericm979 · Jun 24, 2020

NPT is fine for 40 psi water pipes but is terrible for 2100 psi hydraulics. However lots of fittings use NPT. I use NPT to JIC adaptors and use JIC for as much as possible. I've not had a problem with overtightening JIC. However I have had a lot of problems with leaking NPT. NPT seals by deforming the threads. Which means they need to be really tight, and if you loosen and reattach them, they'll leak. Use LocTite 545 on the threads. Don't use teflon tape- if you're not careful it will get in the system.

You can get JIC bulkhead fittings to make your bracket. And standard length hoses with JIC female ends are easy to find. Surpluscenter has good prices on them. I use old garden hose to mock up my hose lengths.

You may find that the flat face couplers take a lot of force to connect. Good ag couplers are easier. I like the Pioneer 4200 series.

1/2" couplers seem to be the standard for compact tractor use. They flow more than you need for a grapple, but if you ever want to plug something else in, they're the most likely to be the right thing.

Tomahawk3830 · Jun 25, 2020

Thanks for the input folks - ordered my connectors and hose. Ended up going with premade hoses with NPT so hopefully the Loctite 545 does the trick. Bulkhead JIC front flat face connectors.

RickB · Jun 26, 2020

KWentling said:
JIC is my preferred fittings for hydraulics. Yes you can damage them by over tightening. Small JICs like these would be tightened finger tight and then one flat on the hex. A little more if it leaks. Use bulkhead adapter fittings on the flat face couplings. I know of no coupling with a built in 90, so use elbows there. ORB fittings are good too for the same reason JIC are good. NPT fittings are very commonly used but not the best by far. 1/4" hose is probably fine. 3/8" might be better because of the long run but probably not necessary.

Agreed.