Possible pump failure on Mitsubishi 2050

[MarcusCarr]

I have a Kumaia ST 2040, which is identical to a Mitsubishi D2050FD. I have a feeling that I may have blown my hydraulic pump. Here are the symptoms that occur to the FEL hydraulics and the 3 point lift.

At 2000 RPM, none of the hydraulics work.
At 2500 RPM, the hydraulics are very slow to respond but appear to have their full strength. I pushed the FEL all the way down and it eventually lifted the front of the tractor.

I know that the quick connects have popped apart twice while I have owned the tractor, so I am guessing I deadheaded the pump and blew it up.

Is there a sheer pin in these pumps?
Can I rebuild one myself?
How can I be certain that the problem is really a bad pump?
If a part of the pump was ruined by deadheading the system, what part needs to be replaced?

I fould a replacement pump for $360, but I would much rather repair the problem than throw a whole new pump at it.

Thank you for your help,
Marcus

 

[Soundguy]

Generally the qd's coming apart, and deadheading the pump make it blow a shaft seal.. sometimes you get a ruptured pump housing.

I'd check to see of your crankcase is 'making' oil. In many cases, once the shaft seal goes.. hyd fluid is pumped into the crankcase.. etc.

If there was a shaft key.. and it popped.. you'd likely have no hyds.. or if it was dragging.. no hyds that would exert any real pressure..

Just pull it and see what ya got. An output pressure/flow check will tell you alot.

Soundguy

 

[MarcusCarr]

There appears to be air in the system. When I disconnect the quick connectors, they usually drip with oil. The dripping now looks frothy or foamy. Will this air in the lines cause extremely slow response, which would pick up if I increase the RPM?

 

[randy41]

when was the last time you changed hydraulic fluid/filter? i dont have a FEL but when my lift arms(i mean my tractor's lift arms)act like that i change fluid and filter and its good to go.

 

[MarcusCarr]

I will start with a fluid change and filter clean tonight and see if the problem gets better. If it still fails, it looks like I will be buying a pump.

The pressure is definately there, this is a flow problem.

 

[Soundguy]

Put some oil in a glass jar.. see if it is air entrainment, or water emulsification.

In either case, you have a problem..

Plugged intake/suction filters can cause cavitation.. Suction side air leaks will cause air entrainment... And any water that gets in the system can cause emulsification. If it is water.. the filter needs to be changed, and sump flushed with a dewaterer, preferably, and drained and refilled.

Do some actual checking, and less guessing.

Crack the line on the pressure side of the valve then open the valve and see what pours out in a bucket.. etc.

Soundguy

 

[MarcusCarr]

Interesting that you mention water. We just had three days of hard downpour and I have been digging drainage for all the water. My tractor also sits outside full time. I will let you know what I find when I drain the oil.

Thank you again for all your help

Marcus

 

[rback33]

Put some oil in a glass jar.. see if it is air entrainment, or water emulsification.

In either case, you have a problem..

Plugged intake/suction filters can cause cavitation.. Suction side air leaks will cause air entrainment... And any water that gets in the system can cause emulsification. If it is water.. the filter needs to be changed, and sump flushed with a dewaterer, preferably, and drained and refilled.

Do some actual checking, and less guessing.

Crack the line on the pressure side of the valve then open the valve and see what pours out in a bucket.. etc.

Soundguy

after the milky foam description, my thoughts were water as well...

 

[MarcusCarr]

Here are the results from last night's work on the tractor...and a few pics.

The problem statement is:
at 2000 RPM the implements do not work
at 2500 RPM the implements work very slowly and appear to have full power

Here is what I did.
1. raised the bucket and 3 point as high as it would go.
2. drained the hydraulic fluid in a bucket...fluid looks fine, no froth or discolor
3. gravity dropped the bucket and 3 point. I could hear the oil spraying into the crankcase.
4. disconnected the low pressure suction line from the hydraulic pump and from the crankcase.
5. disconnected the high pressure line from the pump and from the loader valve.
6. removed the hydraulic oil filter...relatively clean...cleaned with compressed air
7. blew air through the low pressure line...there was no obstructions
8. blew air through the high pressue line...there was no obstructions
9. blew air into the loader valve and could hear the last of the oil blowing into the crankcase
10. blew air into the loader valve and operated the 3 point, it lifted. let gravity drop the 3 point and I could hear the oil blowing into the crankcase
11. The air was not enough to lift the weight of the bucket, but I doubt there are obstructions there because the problem statement covers the loader and the 3 point.
12. put everything back together and filled with new hydraulic fluid

Test results:
idle tractor at 2000 RPM, neither the 3 point or loader would operate
raise rpm to 2500, the loader would lift very very slowly and smoothly...same with the 3 point.

I haven't removed the pump yet, but I believe I will be doing that tonight. Unfortunately, I don't know if I would be able to determine a problem if I were to disassemble the pump.

Here are a few pictures...cause we all like pictures =]

Marcus

 

[MarcusCarr]

pump side