Kubota KX161-3 excavator blade

TFordALA

New member

Equipment
Kubota KX040-4
Jun 14, 2021
23
0
1
Alabama
When using the blade to stabilize the machine I release the handle and blade wont hold down ..push the handle again to lower the blade and it goes down and lifts machine but soon as handle is released the blade wont hold the weight of the machine..i am trying to figure out if its the control valve or the cylinder...Anyone have this issue on these machines?
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,116
2,341
113
North of Pittsburgh PA
When using the blade to stabilize the machine I release the handle and blade wont hold down ..push the handle again to lower the blade and it goes down and lifts machine but soon as handle is released the blade wont hold the weight of the machine..i am trying to figure out if its the control valve or the cylinder...Anyone have this issue on these machines?
I have a smaller KX 41- 2V with a similar problem, although mine is not so quick. If I lower the blade to lift the the excavator, it will gradually leak down and I have to keep lowering it while I’m working. In my case the control for the blade is also used to Change the track width.

If I raise the front of the excavator with the blade, then switch the control to the track width operation, I still have a leak down on the blade cylinder. So I’m guessing that my issue is the cylinder itself needing seals replaced. I haven’t got around to it yet since at this point it’s just an inconvenience.

It could be as simple as your blade cylinder needing rebuilt. There are ways to test the cylinder in place. If I can find a very good description I have on how to do that I’ll post it separately. Don’t hold your breath on that though! I saved too much stuff and I never can find what I need when I want it...
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,116
2,341
113
North of Pittsburgh PA
I have a smaller KX 41- 2V with a similar problem, although mine is not so quick. If I lower the blade to lift the the excavator, it will gradually leak down and I have to keep lowering it while I’m working. In my case the control for the blade is also used to Change the track width.

If I raise the front of the excavator with the blade, then switch the control to the track width operation, I still have a leak down on the blade cylinder. So I’m guessing that my issue is the cylinder itself needing seals replaced. I haven’t got around to it yet since at this point it’s just an inconvenience.

It could be as simple as your blade cylinder needing rebuilt. There are ways to test the cylinder in place. If I can find a very good description I have on how to do that I’ll post it separately. Don’t hold your breath on that though! I saved too much stuff and I never can find what I need when I want it...
Found it!

9FFBC022-326B-4D9A-B583-6AE1A1385EBF.png
 

TFordALA

New member

Equipment
Kubota KX040-4
Jun 14, 2021
23
0
1
Alabama
The cylinder is good..is there a bypass valve on the controller somewhere I can check thats allowing the fliud to just run back to the tank?
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,116
2,341
113
North of Pittsburgh PA
The cylinder is good..is there a bypass valve on the controller somewhere I can check thats allowing the fliud to just run back to the tank?
I do not know. How did you determine the cylinder is good?

Curious because I have the same issue but takes longer to leak down than yours does....
 

TFordALA

New member

Equipment
Kubota KX040-4
Jun 14, 2021
23
0
1
Alabama
I used the boom and bucket to lift machine up. lowered front blade to the ground. Capped off cylinder on the extend side and plugged hose on same and then lowered machine weight back onto the blade and cylinder held up the machine with no issues for a good 2 hours..so my issue has to be in the control valve for the blade .I have not a clue where to start on that as it has bunches and bunches of hoses hooked to it.
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,116
2,341
113
North of Pittsburgh PA
I used the boom and bucket to lift machine up. lowered front blade to the ground. Capped off cylinder on the extend side and plugged hose on same and then lowered machine weight back onto the blade and cylinder held up the machine with no issues for a good 2 hours..so my issue has to be in the control valve for the blade .I have not a clue where to start on that as it has bunches and bunches of hoses hooked to it.
I wonder if you could find a pilot operated check valve block that you could add to the blade cylinder?

Sure would be easier than tearing into the control valve assembly to remove the section that needs repaired. Doubt doing so would in any way affect normal operation of the blade…
 

TFordALA

New member

Equipment
Kubota KX040-4
Jun 14, 2021
23
0
1
Alabama
We was talking about maybe a electric solinoid in the line to stop the back flow and add the button on the handle .. the control valve is expensive and alot of lines hooked to it..
 

TFordALA

New member

Equipment
Kubota KX040-4
Jun 14, 2021
23
0
1
Alabama
Its acting as if you got the blade in the float position all the time except when raised up..i cant find anything on how the blade float works on it and how to check it to see if its stuck open
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
5,116
2,341
113
North of Pittsburgh PA
Its acting as if you got the blade in the float position all the time except when raised up..i cant find anything on how the blade float works on it and how to check it to see if its stuck open
Didn’t realize excavator blades have a float function. My little excavator doesn’t.

The check valve block shown in post 8 would disable float if it were used. But it’s operation would be automatic and not require any action on the part of the operator.

Sounds like a normally closed closed electric valve in the line would work, but then to use float you would have to hold the button all the time. Or have a switch there also...

Are you sure there is a float function? Or did you mean it is acting like it has a float function and is stuck in float?

There is a heavy equipment forum that I have a link to somewhere. I will post the link if I can find it. You might find it with google. I think I remember an excavator sub forum there. You might get more specific help there.

There is also an excavator sub forum under Related Equipment (or similar) at TBN.
 

Mbolt512

New member

Equipment
KX161-3ss
Sep 26, 2021
1
0
1
NC
it was a 50 cent O ring in the control valve that was causing the blade to act up.
I'm new to this machine and could really use some help. I have the same machine with the same issue. Which O ring and did you replace it without removing the control valve assembly? Thanks