Kioti Hydraulic Cavitation ( chatter )

[tkh159]

Hello all,

Let the confusion begin...

I have a Kioti DK40 yr 2005 hours 560

I am having a hydraulic issue that i haven't had in the past.

I only hear the chatter when the backhoe or loader is under load.....trying to extend the loader or backhoe "out" passed its limit or "in" past its limit.

Digging with the backhoe generally is fine but at times it seems as though it is weak and for as long as I don't go past a certain point I don't hear any chatter. Also noted my RPM is at 2000 and doesnt really make a difference if it is higher or lower.

Here is what I have done....I drained ALL hydraulic fluid with the loader and backhoe in the "out" positions and put back 12.5 gallons as that is what it holds so says the manual.

I changed the hydraulic filter let the tractor run for 5-10 mins cycled all the valves turned off tractor with attachments in the out positions and checked the level of fluid and it was almost past the furthest point on the dipstick.

I dont understand hydraulics or how to trouble shoot for the problem.

Is there a pressure relieve valve thats needs to be adjusted???

Does my kioti model have a hydraulic suction screen that needs to be cleaned???

I'm totally lost aside from that I checked for signs of damaged hoses or visible leaks and don't see any???

Any help is much appreciated. Thanks

 

[J_J]

When you say weak, to me that means low pressure or cyls leaking.

Have you put a hyd gage on the hyd system and checked the loader pressure, remote valve pressure or the BH pressure. They all should be set the same. The Fel relief valve will be the master.

 

[k0ua]

Could it be an air leak on the suction side of the pump? I know of no know failure mode like this in the DK, but given the number of years, if there is a rubber hose involved it could have a crack and allow air to get into the suction side. This could cause chattering. The DK40, will have a hydraulic vertical filter in front of the right rear tire, and if a hydrostatic transmission model it will have a horizontal hydro filter under the left side step. There is no suction screen. Is the hydraulic filter on tight?

 

[CosperTractor]

Change the hydraulic filter and hydraulic oil.
Start with the easy stuff first and work out from there!
make sure you are operating the engine at the recommended RPM so the hyd. pump is pumping fast enough.
Donald

 

[tkh159]

@ J_J that's good to know. I have made a phone call to a mechanic that works on tractors and asked if he would bring along some hydraulic gauges so we will see

@ K0ua I hope the pump is fine. Well I did change the filter and it is where you indicated so that would make it a hydrostatic transmission model then I suppose. With that said shouldn't I also be having trouble with shifting or some other transmission related issues?

@ Cosper yeah I changed the filter and oil. That stuff might as well be liquid gold as much as it cost and I had to buy three 5 gallon buckets of the stuff good thing you don't have to change the hyrdo fluid that often.

After further inspection I noticed on my loader valve assembly there is a hose that isn't a "quick disconnect" it is a 90 degree fitting that is attached at the bottom of the assembly and you can wiggle it by hand???? Unfortunately it can not be tightened and I don't have a photo of it just the assembly . I also noticed that it was "damped" with oil not wet about 4 inches from the assembly. It is a KL1470 loader.

 

[k0ua]

@ J_J that's good to know. I have made a phone call to a mechanic that works on tractors and asked if he would bring along some hydraulic gauges so we will see

@ K0ua I hope the pump is fine. Well I did change the filter and it is where you indicated so that would make it a hydrostatic transmission model then I suppose. With that said shouldn't I also be having trouble with shifting or some other transmission related issues?

@ Cosper yeah I changed the filter and oil. That stuff might as well be liquid gold as much as it cost and I had to buy three 5 gallon buckets of the stuff good thing you don't have to change the hyrdo fluid that often.

After further inspection I noticed on my loader valve assembly there is a hose that isn't a "quick disconnect" it is a 90 degree fitting that is attached at the bottom of the assembly and you can wiggle it by hand???? Unfortunately it can not be tightened and I don't have a photo of it just the assembly . I also noticed that it was "damped" with oil not wet about 4 inches from the assembly. It is a KL1470 loader.

View attachment 370571

None of those would be in the pickup to the pump path. The three hoses that are not the 4 QD work ports would be flow from pump. power beyond and return to tank hoses. So the flow from pump and power beyond would have pressure on them during use of the hydraulics so if the leak was very big you would have a lot of fluid squirting out. so the return to tank is low pressure, perhaps that is it. But what I am talking about is the path from the pickup in the tank thru the right rear hydraulic filter and its piping on the way to the suction side of the hydraulic pump. If you have a crack or loose fitting you could be sucking in air into your suction fluid flow, this could possibly cause the shuddering you are experiencing. This is just an idea, but it wouldn't take much of an air leak to cause this. If you have an hydrostatic transmission, its filter is seperate and over on the left side of the tractor under the step and it is horizontal. But if you have a gear tractor, you will not have that filter at all.

 

[J_J]

None of your loader hose should be loose.

Can you see which port it connecting to?

Most cavitation is caused by a suction restriction, or when any relief valve is relieving.

Do you have bubbles in the fluid? That is usually caused by a suction leak.

 

[tkh159]

No bubbles that I can see.... The only suds/bubbles I can see are withing the front axle which I'll attach a photo but I don't think thats hydraulic fluid

So here is the update. Had a guy come over with some gauges that tapped into my loader. The pressure reading was 2300-2380 the gauge was VERY responsive to the movement of the loader and when not moving it stayed above 2300 soooo I would assume there isnt a leak????

Any way going to attach some photos and one video and see what you all think. The first couple seconds is the noise I hear more often.

The person who came by with the gauges seems to think that the pressure release ( or relieve ) valve needs to be replaced as he seems to think it is having trouble opening/closing??? Any thoughts on that ?

I wanted to post what he pointed out was the valve of replacement.







[video]https://plus.google.com/101128254393057736151/posts/c17ctyrLxGd[/video]

 

[k0ua]

What happens in the front axle stays in the front axle. The front axle does not share fluid with the hydraulics or transmission. I hate to say this but I did not get much out of your video except a look at the joystick motion diagram. That doesn't do me much good. I saw you or someone pushing the joystick forward for a second or two and I heard the relief valve opening. But that is about all I got out of it.. Move the camera back about 6 or 8 feet, and show the joystick action and the loader action.

 

[k0ua]

Main Relief pressure should be: This is for the Later DK45se.. so not sure if that applies to your DK45.

* Main relief pressure: 188.6 kgf/cm2(18.5 MPa, 2.683 PSI)

So it appears your main pressure relief might be low If it should be the same as a Dk45se. I don't know for sure. A shop manual for your exact model would be nice.

 

[k0ua]

Main Relief pressure should be: This is for the Later DK45se.. so not sure if that applies to your DK45.

* Main relief pressure: 188.6 kgf/cm2(18.5 MPa, 2.683 PSI)

So it appears your main pressure relief might be low If it should be the same as a Dk45se. I don't know for sure. A shop manual for your exact model would be nice.

 

[tkh159]

I'll see about getting a better video. Mine is a DK 40 and the setting for that loader is 2450 psi