Kubota L5030 (no Hyd functions)

[johnpawl]

First post here. Thank you for hearing me out.

My friends owns a L5030 that's out in the field right now.. I'm looking for some basic knowledge / info on this tractor before I head out there to tackle the job.
I have the service manual and I'm also a Mechanic by trade, so I'm not looking for a silver bullet but just maybe some things to look at right off the bat.

From the info I have gathered he said that he has no hydraulic functions at all. PS, implement and cylinder operation for the front will not work at all.
He took the dual pump out and had some people go through it without there being a problem found. Looking at the hyd schematic the PS runs through the front half and cylinder operation through the back half. I'm going to say the pump is OK for now. Is there a bleed procedure on this pump?
Now for the kicker. After spending a few hours explaining to him how the Hyd system operates and a few things to check for himself (before I drove out there) He mentioned that the tractor will not even go into forward or reverse. This was news to me but now I'm thinking I have a different problem. Maybe related, maybe not because it seems the systems are separate.

So where should I start when I get out there? What should I look for first? Are there any common problems with these units that I should be aware of?
Hopefully this will be a laugher and take 10 minutes to fix.

Thanks for your time, very much appreciated.

John-

 

[bigbull338]

ok is the tractor an hst or gear tractor.from what your saying im still leaning towards the hydro pump being out even though he had the pump checked.also what was he pulling an doing with the tractor when the pump quit on him.

 

[johnpawl]

ok is the tractor an hst or gear tractor.from what your saying im still leaning towards the hydro pump being out even though he had the pump checked.also what was he pulling an doing with the tractor when the pump quit on him.

GST model

He uses it to bush hog. He didn't say if he uses the front bucket for anything, but he doesn't have anything heavy to lift that I know of.
One morning he hopped on the tractor and nothing was working. (or so, that's what I was told) Guess we can take that with a grain of salt.

 

[bigbull338]

im still betting the pump is out.

 

[k0ua]

Maybe not sucking up any fluid from the "tank" ? Does it have a suction hose with a big hole in it? or is it metal piped? just guessing here. But if you cannot develop any pressure ( a quick gauge check should tell that), and fluid is in the transmission/tank and not all out on the ground, perhaps none is getting into the pump from the suction side? Again.. I am no mechanic, and these are just guesses from thousands of miles away

James K0UA

 

[Tx Jim]

Possible pressure relief valve is malfunctioning. I presume simple tasks have been performed such as checking hyd fluid level and changing hyd filter.

 

[johnpawl]

Was just told suction line is soft-
No leaks or air sucking from lines-
Fluid and filter recently changed with proper fluid-

 

[dkf435]

Service manual flowchart says no 3pt then clogged filter, if only steering down defective pump. If everything works and no motion start checking GST. There is a regulating valve that feeds GST and steering .

Must go now be back later but check filter, pump and suction line.

David Kb7uns

 

[johnpawl]

Will be checking back after the weekend. Going on a mini vacation. :drink:

 

[k0ua]

Was just told suction line is soft-
No leaks or air sucking from lines-
Fluid and filter recently changed with proper fluid-

So the suction line is collapsing then?

James K0UA

 

[texasjohn]

You're a mechanic and have the manual. You'll figure it out.
Got to be something simple since failure was sudden and all encompassing.
given that there actually is fluid, functioning filters, that all hoses are properly connected....there are quick connects that have to be properly installed for FEL to work...that there is hydraulic pressure...not too hard to determine...and that the pressure relief valve is properly installed....then the pressure pump seems at fault.
However, since there has been someone messing with the system...I'm going to bet that the pressure relief valve (see manual to find) was not properly reinstalled. Listen for it to hiss...

After you see the tractor, come back with more details...those of us with an L5030 can offer ideas...but the hyd system has been flawless for me and I do not recall any other posts of gross hyd failure...it's gotta be something simple....

 

[johnpawl]

So the suction line is collapsing then?

James K0UA

I would think so although his description was that it's soft.

 

[johnpawl]

You're a mechanic and have the manual. You'll figure it out.
Got to be something simple since failure was sudden and all encompassing.
given that there actually is fluid, functioning filters, that all hoses are properly connected....there are quick connects that have to be properly installed for FEL to work...that there is hydraulic pressure...not too hard to determine...and that the pressure relief valve is properly installed....then the pressure pump seems at fault.
However, since there has been someone messing with the system...I'm going to bet that the pressure relief valve (see manual to find) was not properly reinstalled. Listen for it to hiss...

After you see the tractor, come back with more details...those of us with an L5030 can offer ideas...but the hyd system has been flawless for me and I do not recall any other posts of gross hyd failure...it's gotta be something simple....

Thanks, John. I'll get more info up after I get back from looking at it. Yep, it sounds like something basic.

 

[J_J]

If you say the fluid level is OK and the filters are new, and the engine is running, then the pump must not be sucking fluid.

If someone checked the pump out, what does that mean, Did they connect it up and pump fluid?

If the tractor is HST, that pump is separate from the implement and steering pump.

So if you have no fluid being pumped to the steering and the implements, there must be no fluid getting to the pump.

Remove some hoses and check flow, and how much.

If the fluid level went low at some time, the pump may need primed,

A hyd gage would certainly help to establish pressure when and where.

If you think the suction hose is collapsing, look at it before you start engine, and then look at it after you start the engine.

 

[johnpawl]

Update: I finally got around to looking at this tractor. Found a small pinhole in one of the metal lines.
This was sucking air and made the pump lose prime. Line is repaired and everything is good now.
Thanks for all the feedback. Sorry it took so long to post the fix.

 

[moship]

Any ideas what caused the pin hole?

 

[k0ua]

Update: I finally got around to looking at this tractor. Found a small pinhole in one of the metal lines.
This was sucking air and made the pump lose prime. Line is repaired and everything is good now.
Thanks for all the feedback. Sorry it took so long to post the fix.

Thanks for checking back, that is kind of what I figured, No fluid going to the pump, only air...That would do it.

James K0UA

 

[johnpawl]

Any ideas what caused the pin hole?

Rubbing/vibration against the frame.

 

[moship]

Do you think it is something all Grand L30 owners should check for to prevent a similar issue? Is it possible to photo the general location of failure point?

 

[johnpawl]

Do you think it is something all Grand L30 owners should check for to prevent a similar issue? Is it possible to photo the general location of failure point?

here is the pic you asked for.