Kubota B26 blowing oil from vent

[3Ts]

I'm not clear on what the problem is since I don't have a "B", but I do have a comment that may apply. On the L series tractors there is a vent tube under the seat that mud daubers find every once in a while and plug it up. When they do plug it up, the transmission leaks oil around the shift levers. So be sure your tank vents are clear.

 

[100 td]

I have..... replaced hydraulic filter thinking it was sucking air

Whilst I'm sure you're good with this, just to clarify, you replaced the hydraulic filter under the tractor on the RHS, not the HST filter on the LHS? Many times a problem happens and we find a description was not quite right and something being done was not done.
Was it a kubota filter?

 

[rScotty]

Thanks, it is lowering it's on fluid plus I changed the suction filter and had to add oil back to it making sure I stayed just below the mark. The filler cap is not vented but the vent is right next to it and that is where the hydraulic oil is blowing out, now when I say blowing I mean pressure will continue to come out the vent tube after the oil stops.

I've got a couple of questions. First of all, did you do any maintenance on the tractor right before noticing the oil blowing out the breather? I hope that doesn't sound too simple, but it's always the most obvious place to look.

And let me see if I have this right....It doesn't immediately start to blow oil out the breather; it needs to run awhile first? And what does the oil on the dipstick look like when it begins to blow out the breather? Is it foamy? If foam, do you think that is from air being entrained into the oil? Any sign of water? Water in hydraulic oil looks a lot like foamy chocolate milk. A drop of suspect oil on a piece of blotter paper will show a jagged outer ring as compared to clean uncompromised oil.

Are you saying that it blows oil out for awhile and then stops blowing oil but keeps on blowing air while it runs? Does operating the hydraulic controls change how much pressure is coming out the vent?

OK, lets suppose it is entrained air from the suction side of the pump, and that is bulking up the volume until the excess oil (partly foam) is blowing out the breather. If you checked the hyd oil when it is blowing oil then at that time it would show as being way overfull and bubbly on the stick. And then after the tractor sat and the oil settled down the dip stick would show the normal amount. Is that happening? If that is the case, I would think that the hydraulic cylinders would work differently when filled with foamy oil than they do when starting out cold. You might even see the hydraulic cylinders take a moment to fill up from cold..... or if they have a load on them they could even sag an unexpected amount either overnight or just after starting up. Or even jump when first actuated.
rScotty

 

[woody]

Whilst I'm sure you're good with this, just to clarify, you replaced the hydraulic filter under the tractor on the RHS, not the HST filter on the LHS? Many times a problem happens and we find a description was not quite right and something being done was not done.
Was it a kubota filter?

Both I replaced both filters while I was under there getting oiled up, man I should not squeak for a long time.

 

[woody]

I've got a couple of questions. First of all, did you do any maintenance on the tractor right before noticing the oil blowing out the breather? I hope that doesn't sound too simple, but it's always the most obvious place to look.
And let me see if I have this right....It doesn't immediately start to blow oil out the breather; it needs to run awhile first? And what does the oil on the dipstick look like when it begins to blow out the breather? Is it foamy? If foam, do you think that is from air being entrained into the oil? Any sign of water? Water in hydraulic oil looks a lot like foamy chocolate milk. A drop of suspect oil on a piece of blotter paper will show a jagged outer ring as compared to clean uncompromised oil.

Are you saying that it blows oil out for awhile and then stops blowing oil but keeps on blowing air while it runs? Does operating the hydraulic controls change how much pressure is coming out the vent?

OK, lets suppose it is entrained air from the suction side of the pump, and that is bulking up the volume until the excess oil (partly foam) is blowing out the breather. If you checked the hyd oil when it is blowing oil then at that time it would show as being way overfull and bubbly on the stick. And then after the tractor sat and the oil settled down the dip stick would show the normal amount. Is that happening? If that is the case, I would think that the hydraulic cylinders would work differently when filled with foamy oil than they do when starting out cold. You might even see the hydraulic cylinders take a moment to fill up from cold..... or if they have a load on them they could even sag an unexpected amount either overnight or just after starting up. Or even jump when first actuated.
rScotty

Okay thanks for helping and at this point nothing is to simple, the tractor will run maybe two minutes and it does not matter if I move anything or not and I have tried it both ways and the blowing/foaming will start, now if I pull the dip stick out oil will come out of the dip stick hole because it is lower than the vent tube and it is already coming out the vent. Yes the oil looks foamy and I was thinking at first it could be water in the system but I have ruled out the water so it has to be air, did not know that about the drop of oil on the paper interesting. when I let the oil blow out for a few minutes and caught some it only took a few minutes and it cleared up and looked just like hydraulic oil should look.

it will blow out as long as the tractor is running and after I turn the motor off it will blow out air and oil and then eventually just air for awhile. when I first noticed it I turned off the tractor and after looking around trying to figure out what was happening I started it back up and since it wasn't blowing out I finished my work but it did start blowing out I just don't know how long before it started that day, but now it only takes a few minutes.

your last paragraph is a yes that is exactly what is happening, I tightened the clamp on the suction side of the pump and it made no difference, I changed the oil filter with no difference. I tried looking and feeling of the rubber elbow at the pump and could not find a split or hole in it.

 

[woody]

I'm not clear on what the problem is since I don't have a "B", but I do have a comment that may apply. On the L series tractors there is a vent tube under the seat that mud daubers find every once in a while and plug it up. When they do plug it up, the transmission leaks oil around the shift levers. So be sure your tank vents are clear.

the tank vent is where the oil is coming out.

 

[woody]

I am thinking now that maybe the pressure relief valve is stuck open or has trash in it allowing the tank to become over pressurized. is this possible?

 

[wagne223]

I am thinking now that maybe the pressure relief valve is stuck open or has trash in it allowing the tank to become over pressurized. is this possible?

Since you say the oil is foamy, that is evidence that air is being introduced.

If the vent is clear, even in full bypass the tank will not pressurize. Your problem is air intrusion.

I know you changed the filter and tighten a clamp, however you have not actually found the source of air intrusion.

Sorry I can't give you advice on where the air is getting in, but that is the issue.

 

[woody]

Since you say the oil is foamy, that is evidence that air is being introduced.

If the vent is clear, even in full bypass the tank will not pressurize. Your problem is air intrusion.

I know you changed the filter and tighten a clamp, however you have not actually found the source of air intrusion.

Sorry I can't give you advice on where the air is getting in, but that is the issue.

I agree and air was my second thought, water was first but I haven't found anything yet but I will be looking. this working is getting in the way of me fixing my tractor.

 

[100 td]

My thoughts from afar, what I would do with the same symptoms, after replacing filters with OEM parts. You have a 10 year old machine, the following is cheap and relatively easy maintenance in the scheme of things, and will help to fix, or rule out some bits. The most likely cause of aeration is the suction elbow, remove and physically inspect, squish/feel/replace, if at all hard or any sign of deterioration. However there are a couple of other orings in the circuit, and are worth doing while you are there. Remove suction line and oil filter housing, replace oring to tank and oring to line. So order the parts, fit them, and see if any improvement. The drained oil can be put back into tractor, run it through a sheet if any debris has dropped in it. YMMV.