Help with old Kubota

[CT18fireman]

I am working on my neighbors old (1980 I think) Kubota L245DT. We are having a problem with the hydraulic system. It will lift the three point with his york rake on it but not really fast. The main problem is with the L1200 loader. Last week it would pick up the front of the tractor by using down pressure, I did so to change the tires for him. Now it will lift the bucket with a small load but not lift the tractor by going down, also the bucket has no curl force. It is a two lever valve for the loader. The pump is mounted out the back of the injection pump on the 3cyl motor. The loader hoses come off the transmission right below the seat.

I have a pressure guage loaned out to a friend, he is bringing it back tomorrow. Just seeing if anyone remembers anything on these. Trying to get it working again for this guy.

 

[bill onthehill]

Seeing that you have problems front and rear I would look for a relief valve bypassing or the pump may be shot. Does it have a suction strainer for the pump?

 

[CT18fireman]

It has a strainer mounted in the bottom of the transmission which serves as the resevoir. I took the strainer out it had just a bit of grime on it but cleaned it anyway. He has a parts manual but not a service manual. So I can find the location of things. I see that the relief valve is under the seat to the left so I will pull that apart tomorrow to check for grime.

 

[CT18fireman]

OK On my inspection today I found that the three point lift works fine. It would lift over 1000lbs no problem. The front loader though will not lift more then itself and a couple hyndred pounds and as said won't curl the bucket with weight in it. I just get a squeal up at the loader valve control. Thinking its either not getting good pressure into the loader circuit or maybe there is a relief valve in the control that is stuck.

 

[wildhorse trnr]

Do you have the ability to check the relief pressure for the lift circuit?
If so and it is in need of raising, that would be a quick fix as long as it will adjust up, if it is low but you have trouble getting the pressure up, your pump may be in question. Check the pressure with no load in bucket and dead head the lift circuit.
Also, I am not sure of that particular system(no schematics) but you might want to check for a load check or anti-cavitation(replenishing) valve, I have had those fail and the unit would not build proper pressure and it would make a chatter/squeal noise, but that was on older bobcat units.
Before R&R of a pump I always pull the filter and cut it open to check for brass.

 

[CT18fireman]

I have a hydraulic pressure guage. Having trouble getting to what I think is the relief.

In the first photo you see the valve In pressure is closest to the steering wheel.

Next is lift circuit and the curl and then out.

 

[CT18fireman]

In this picture you can see the power beyond. Pressure comes from the line from the bottom of the pic. Then into lower hose up to valve then back down upper hose and out to three point lift. There is a relief valve under the seat but it is clean and tight and the three point as said will lift 1000lbs at least at idle.

The squeal I get is from the valve and sounds the same as when I max out the cylinders only it happens with a load when there is lots of travel left.
He has the parts manual so I can locate components but not a service manual with pressures, test procedures etc.

 

[gravey]

Jessie

Is the oil supply lines correct in is in out is out. might try switching them.

is this the right loader valve closed center or open center may be w/ wrong valve could be just by passing.

good luck

Gravey

 

[willie59]

I'd be willing to bet you have either a failed relief on the loader valve, or, you have failed o-rings on the relief cartridge of the loader valve. You gotta find that relief valve.

 

[stock]

My the grey sells are poor but years ago I worked on a buta and this is my take on the valve chest..

 

[CT18fireman]

Yes that is correct. I did get the relief valve open. It was a ball type as you can see in the pic. The ball then fell out of the socket so then I had no movement at all. I took the valve off so I could get the right angle to get the releif valve back together. It had some movement left before I took it apart so I am going to do the following next, put valve back in about where it was, Tee in a pressure guage to the "in" line on the loader so I can see what the pump is producing up to the valve, turn the releif valve a bit to see if I get more power.

On a Kubota site I also posted on they mentioned it could be the cylinders are worn and leaking past the seals inside, just seems odd to happen to all four at once.

I am just home for lunch and only fiddling with this thing at night for the guy so I will let you know what happens next.

 

[stock]

Yes that is correct. I did get the relief valve open. It was a ball type as you can see in the pic. The ball then fell out of the socket so then I had no movement at all. I took the valve off so I could get the right angle to get the releif valve back together. It had some movement left before I took it apart so I am going to do the following next, put valve back in about where it was, Tee in a pressure guage to the "in" line on the loader so I can see what the pump is producing up to the valve, turn the releif valve a bit to see if I get more power.
.

Right the valve has slackened off or jammed open,Do not put the clock on the pressure supply pipe tee it in to the main lifting service, the pipe going out to the lifting cylinders.If you use the main supply pipe the main relief valve will come into play first, you don't want this. What needs to happen is the loader valve trips before the main valve. you need to know the pressure that the main PRV releases at and be the same or slightly under that.

 

[CT18fireman]

Took it all apart, cleaned it and then put it back together. Works fine now. Still have to adjust pressure releif but it is working. Probably going to end up replacing valve since float does not hold either. Missing parts probably to hard to find.

Thinking that the releif ball just got stuck off center or something. He's happy now and I can "borrow" the machine when I need to until I get my tractor purchase figured out.