Oil blows out overflow on Kubota B5200

[Bladeharvest]

Thanks for the suggestion.
We just replaced the lift pump as suggested earlier in the post. ($60 US) I have not run the machine long enough to test it yet, just long enough to bleed out the lines and new fuel filter. I decided while it was down to do a little maintenance on the hydraulics but because of the holiday it will not be done till next week. When I get it back together I will run it and let you all know if it was the lift pump.
Kubota and one of our fellow members suggested the pump cam as the next culprit. I will mention your observation to the mechanic helping me troubleshoot this.
Thanks for all of the great input!
Bladeharvest

 

[jinman]

Have you checked your hydraulic fluid level yet? Your hydraulic pump could also have a blown shaft seal and be dumping fluid into your crankcase.

 

[Eagleview]

Have you checked your hydraulic fluid level yet? Your hydraulic pump could also have a blown shaft seal and be dumping fluid into your crankcase.

X 2 ..

 

[Bladeharvest]

Have not thought of that yet. Will check.
Thanks!

 

[Bladeharvest]

Just had time to check Hydraulic fluid. Low. It was topped off not too long ago when machine was serviced. I am rebuilding the cylinders and the pump next week. Hope this is the problem solver.
Thanks for the great posts.

 

[dcyrilc]

Just had time to check Hydraulic fluid. Low. It was topped off not too long ago when machine was serviced. I am rebuilding the cylinders and the pump next week. Hope this is the problem solver.
Thanks for the great posts.

Since the hydraulic fluid was low, check you crankcase oil level as well. If it is overfilled, you found your missing oil and why it was blowing fluid.

 

[Bladeharvest]

Ran the tractor for a couple of hours today. Hydraulic fluid and oil levels are stable.
We replaced the shaft seal on the hydraulic pump as was suggested. While doing so I also replaced all cracked or checked hoses on the loader and replaced all of the o rings in the cylinders.
I noticed that the loader performs much better but the 3 point has started acting funny. Occasionally while driving even at high rpms it drops slowly. I have checked the control and it is in the center position. On the other hand I was grading a driveway and it held to the point where I had lowered it to.
I wonder if the front loader control valves may be worn and allowing some fluid through. When parked the bucket will slowly rotate down. Sometimes it takes a few minutes, other times it takes a couple of days. I talked with the local Kabota dealer, they have no clue. I have had better suggestions here than from their repair dept.
Any input is appreciated.

 

[killdozerd11]

Ran the tractor for a couple of hours today. Hydraulic fluid and oil levels are stable.
We replaced the shaft seal on the hydraulic pump as was suggested. While doing so I also replaced all cracked or checked hoses on the loader and replaced all of the o rings in the cylinders.
I noticed that the loader performs much better but the 3 point has started acting funny. Occasionally while driving even at high rpms it drops slowly. I have checked the control and it is in the center position. On the other hand I was grading a driveway and it held to the point where I had lowered it to.
I wonder if the front loader control valves may be worn and allowing some fluid through. When parked the bucket will slowly rotate down. Sometimes it takes a few minutes, other times it takes a couple of days. I talked with the local Kabota dealer, they have no clue. I have had better suggestions here than from their repair dept.
Any input is appreciated.

The bucket control valve has a bypass leak in the spool it sounds like
a bad o ring or worn valve spool or valve body

A small piece of metal shavings or dirt maybe nicked the o ring
But also o rings will go bad with time or heat

Also i don't know about kabotas but some cat equipment can bypass leak between the trans and the engine causing it to transfer oil into the crankcase and vice versa

 

[Bladeharvest]

Thank you,
It would appear at this point that the problem was a worn cam seal between the hydraulic pump and the engine. I have run it for several hours now and not seen any difference in the oil level nor the hydraulic fluid level.
Your suggestion that it might be a leaking bypass sounds correct. I intend to check that the next.
Thanks for the input!

 

[Bladeharvest]

Update:
Have run the machine now for quite a few hours doing some grading and light backfill. The hydraulics as I mentioned earlier were starting to do the same thing as they did before, ie three point does not stay up but slowly drops and the front loader slowly lowers and the bucket rotates.
I checked the oil level in the crank case and it has started to make oil again. The hydraulic fluid appears to have dropped.
Could the cam seal have blown again? Should I rebuild the entire pump? A new one costs nearly $800.
If the fluid is leaking back into the crank case, would this explain the hydraulics not holding pressure since it would be bleeding off into the engine?
Thanks for all of your input it has been very helpful.