Kubota, Leaky fitting, anyone familiar with this one?

[joea99]

This fitting is attached to the side of the hydraulic cylinder where it transitions to the hose connection, Kubota part # 75590-13270. Same or similar fitting appears on all the Kubota cylinders I've seen.

It, or the hose fitting, appears to be leaking. This one happens to be on one of the boom swing cylinders, so it pretty hard to get at. Just looking for some idea of what I am facing to pull it out. I've rebuilt a couple Kubota cylinders with similar/same fitting and never needed (or dared?) to take them off.

 

[LD1]

Not sure what the question is in here.

Take the hose off and unthread the fitting. Likely either a NPT fitting or ORB fitting on the cylinder side and JIC where the hose connects.

But its unlikely the fitting itself needs replaced. Unless you banged it into something. Might just need taken apart, cleaned, and new thread sealer if NPT or a new o-ring if ORB. OR the JIC needs tightened a little bit. You didnt say "where" it was leaking from

 

[joea99]

Not sure what the question is in here.

Take the hose off and unthread the fitting. Likely either a NPT fitting or ORB fitting on the cylinder side and JIC where the hose connects.

But its unlikely the fitting itself needs replaced. Unless you banged it into something. Might just need taken apart, cleaned, and new thread sealer if NPT or a new o-ring if ORB. OR the JIC needs tightened a little bit. You didnt say "where" it was leaking from

I can't tell what exactly is leaking, due to position and dirt. I can only tell drops form where the hose (actually steel pipe) joins the right angle fitting that goes into the cylinder. Most of the caked on stuff is scrapped off now, but, of course, it is now "dripped dry".

Close as I could tell, the fluid was forming around the threads of the JIC nut, but, it could have been running down from a crack. Originally feared, but did not think, they cylinder or fitting was damaged, but, since I was working in a very rock area being cleared of trees, it is possible.
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Guess the only thing to do is pull it out and check. Probably take most of the day just to get it clean enough to work on.

Part of the question was about the fitting itself, Kubota calls a "plug". In the light of a new day, I see the part is actually a "plug" that screws into the "fitting", which is actually welded into the cylinder, from the looks of things. Attached is a view, with item 70 being the plug. My fear is I may have cracked the welded in part.

 

[Carl_NH]

I took a look at mine and it would seem you should remove the BH to get better access to the back of the cylinder. Also you are correct there is a nut in the end of the welded fitting with a hex head.

I would doubt that would loosen up, and unless you got something jammed in between the swing and frame this could break the weld - either way, it can be rewelded.

 

[joea99]

I took a look at mine and it would seem you should remove the BH to get better access to the back of the cylinder. Also you are correct there is a nut in the end of the welded fitting with a hex head.

I would doubt that would loosen up, and unless you got something jammed in between the swing and frame this could break the weld - either way, it can be rewelded.

The BH is detached. Resorted to the old standby of brake cleaner to degrease, compressed air to dry, and baby powder to show wetness. With the aid of a mirror (oddly enough I found one where it should have been) seems the wetness grows around the rim of the circular plug and eventually drips off. Appears there is an o-ring in there that may have failed. Annoying as I just donated over $400 to Messicks for seal kits for every cylinder on the BH (except one done last year) but did not include that plug.

Looking on the possible bright side, I may be able to replace that plug, or just the o-ring and get back to work, leaving the cylinder re-seal job for a winter project. Hoping no more 16 year old seals or hoses give out.

I am a bit skeptical about being able to remove that plug without a great deal of suffering. Kubota sells the plug with the seal, presumably a standard ORB type o-ring, but hopefully I can find a proper ORB size in my parts locker.

 

[Carl_NH]

Joe - yes the original tightness/torque on some of these could make it a bear to remove the nut, but with an o-ring seal you wouldn't think they would need to tighten too much. Glad you found the leak too!

Just get a good fitting allen wrench and give it a go - might need some heat assist.

 

[joea99]

Joe - yes the original tightness/torque on some of these could make it a bear to remove the nut, but with an o-ring seal you wouldn't think they would need to tighten too much. Glad you found the leak too!

Just get a good fitting allen wrench and give it a go - might need some heat assist.

Escaped my notice earlier, but seems someone has been in there before. The hex is "hogged out" so the 3mm that fits the other similar plugs is too loose. 4mm does not fit. The paint around the rim of the plug is gone and has that tell tale look of a slipping vise grip. Suspect I see a hint of extruded sealer as well.

Seems like vise grips will get a test today. But I will wait a while, maybe someone has a better idea.

 

[KWentling]

I've had luck sometimes driving a Torx bit into a rounded out hex.

 

[joea99]

I've had luck sometimes driving a Torx bit into a rounded out hex.

Space is pretty tight. Seems I will have to at least remove a hose, maybe pull the cylinder

.

 

[joea99]

Managed to get a torx in there after moving the cross over hoses away, but it broke immediately. Chinesium bit, hollow apparently. Odd.

Finally got it out with a long nose vise grip after much coaxing. The seal is definitely blown out and is not a black oring but kind of yellow green, almost like ac (freon) oring. Certainly not going to use that plug again, so, I'll just order up a couple plugs with seals. I hope. It's only money.