So a couple of weeks ago right down the street from my yard I see this Kubota parked kind of by the main road but not really that close, so I go back to have a look and it's for sale, the sign had fallen down inside the cab, was in very good condition, with enclosed cab, heat, quick tach, 18" bucket with the teeth in sorry shape, no thumb, with 1000 hrs on it. Call the #, guy tells me what he wants for it, set up a time to meet, and bought the little bugger. Just put a thumb on it and was wondering if anyone has any idea how to adjust the aux hydraulic relief so I don't rainbow the cylinder?
On my kubota....when you add thumb it comes with its own relief valve kit that has to be added
It looks like after doing some more research, this machine is a dash 3 with the thumb bracket on the stick and the "intllipanel" so it comes with the relief valves already installed for "quicker and simpler installation of the thumb attachment" per the Kubota manual and brochure.
Well, after actually looking at the valve today it doesn't have the relief valve, apparently there is a serial number break when it became "standard equipment" mine is a few numbers shy...figures. So I looked it up and they show two, one for each side at $544 each. Is it all that bad to just add one on the "closing" circuit?
No has to be on both circuits...when you curl bucket it has to relief...but you can get reliefs WAY cheaper that...if you can rig a cross over relief than no need to return to tank...and cheaper
I am in the same situation. Is it possible to set the pressure for the circuits below the pressure of the bucket curl setting to resolve the problem?
NO!!!!! Do NOT use just a crossover relief with a cylinder! You MUST have a return to tank! The difference in piston area between the butt end and the rod end will cause pressure intensification and whichever component is weakest will explode. I have seen the aftermath with blown hoses, a catastrophically ruptured cylinder, and actually a crossport valve that literally split in two. A crossport relief valve with tank return IS acceptable. Or two single reliefs with makeup checks and with both drains connected to a tank line will work.
Good day We have published considerable amount of information regarding thumb hydraulics and control this can be found at excatech.org >Library > Adapted applications. the files are heavy with illustrations to heavy to post here but you can down load these its safe & free. trust it will be helpful. Kind regards Uffex
Just looked at manual that's odd theres no adjustment. The blade spool has adjustment. We had alot of these in the rental fleet and never had a problem with thumbs. Larger machines would break the pin if pressure wasn't reduced for thumb.
Can you tell me the serial number break? I'm about to go look at a KX71-3, and it will need a thumb, so I'm trying to figure out how hard that will be.
You can look up parts here to see serial break but from service manual I dont see it being an option on the 71-3 https://apps.kubotausa.com/illustrated-parts/
#60 is service port it shows reliefs but no serial break. Does the valve have plugs where reliefs could go
So, just to update, I ended up buying the relief valves from Kubota, they aren’t cheap, but it was way easier to install them instead of doing extra plumbing on the stick.
You have a part #, or a pic of the install, or anything. I'm still trying to figure out what I'm looking for when I look at this machine.
Like I said upstream, there was a serial # break which meant it had the reliefs or it just had plugs, mine had plugs....I belive I looked it up on Messicks site and got the part #s there. I can look to see if I can the part #. It was fairly simple to install, removed the floor plate and the valve is right there, it's a little tight to work in there but possible. My machine is out on a job, when I head there again I'll grab some pics.