loss of hydraulic control

72chevy4x4 · Jan 14, 2009

I have a Kubota L3540HST, it's a sweet ride with about 85 hrs on the clock. Last summer I was having a quirk w/ the hydrualics not always going down smoothly. Well, I forgot about it and the problem went away (not sure how that happens). I'm pulling up asphalt w/ my forks and drove into the asphalt at an angle (like dozer blade position).

now there is no hydraulic up pressure for the curl function (bucket up). curl down works fine. Boom up and down are fine too. I was messing with it by putting the bucket full curl down and driving backwards while applying down boom pressure, and the bucket does curl up (just not under hydraulic pressure). I 'think' hydraulic fluid is getting from the loader valve to the cylinders, just not sure what's going on.

As a form of diagnosing the problem, can I swap the hoses on the loader valve (the quick connects) and see if boom up function goes away and curl up works? If so, that would indicate the loader valve is the culprit.

thoughts? thanks!

kennyd · Jan 14, 2009

As a form of diagnosing the problem, can I swap the hoses on the loader valve (the quick connects) and see if boom up function goes away and curl up works? If so, that would indicate the loader valve is the culprit.

This would be a great place to start. I suspect that you have a bad Quick Coupler that is causing you grief.

72chevy4x4 · Jan 14, 2009

so, maybe by resetting the quick connect, it could allow fluid motion?

here's a question on function: when I apply bucket up, does the fluid go in one hose and come back in another?

kennyd · Jan 14, 2009

Yes, reseating QD's often cures problems like this. Sometimes they "look" connected but are not seated alll the way.

here's a question on function: when I apply bucket up, does the fluid go in one hose and come back in another?

Yes. There is fluid in the other end of the cylinder, so it's forced out and back into the tank.

jimainiac · Jan 15, 2009

Just from experience, I would suspect the quick coupler, also. I've had one of the couplers for the loader start leaking for no reason, and undoing it and reconnecting it fixed it. Since they're designed to stop the flow when not connected properly, maybe that's it. If you tried switching the bucket curl hose with the lift hose, would you have to also switch the other two hoses?

jimainiac · Jan 15, 2009

I just thought of another possible cause of a loader control problem, that would only show up in subfreezing temperatures. A couple of winters ago my loader control started to get a little balky in cold weather and someone on TBN said to check to see if there were drain holes in the valve. There weren't, and as per their instructions I drilled eighth inch holes in the valve on a mild day. Out dripped a bunch of water. Condensation forms in there and needs to be able to get out. I had a friend who was having the same problem and drilling the drain holes fixed his, too.

72chevy4x4 · Jan 15, 2009

the tractor is at the dealer getting fixed-will let you guys know what the verdict is. It is not the coupler. I swapped lines (boom for bucket) and the problem went to the boom but then the bucket wasn't working correctly in one direction. Me thinks it's a cylinder :-(

dealer said it's under warranty. What is the warranty period on the Kubota tractors?

72chevy4x4 · Jan 17, 2009

the dealer called w/ the verdict-said the cylinders are literally bowed (assuming in full out position). dealer indicated Kubota likely won't pay for repairs. Can anyone comment on Kubota warranty repairs or source for cylinders? I'm guessing the dealer would charge an two arms and a leg for the parts/labor.

jimainiac · Feb 8, 2009

72chevy4x4 said:
the dealer called w/ the verdict-said the cylinders are literally bowed (assuming in full out position). dealer indicated Kubota likely won't pay for repairs. Can anyone comment on Kubota warranty repairs or source for cylinders? I'm guessing the dealer would charge an two arms and a leg for the parts/labor.

What was the outcome of the repairs and charges to fix the loader cylinders? Haven't heard from you, hope you didn't have a heart attack when you got the news...
What do you think caused the damage?

72chevy4x4 · Feb 8, 2009

there are nuts at the back of the cylinder which if they back off, causes damage (all info according to dealer). since that was the cause of damage to one cylinder, the other cylinder may bend b/c of the unequal stress. So...the repair didn't cost anything, all though they didn't put in new rods--they welded the old end to a new(or newer) rod for both sides. Not sure what the deal was with the welded rods??