M59 hydraulics got slow and weak.

[rScotty]

......... So the foaming has to be bad. I am running the new synthetic Kubota fluid. Maybe change to new fluid?

You might be thinking of the posts we had on that subject earlier. (posts #56 & #107...I think....)

At 200 hrs changed to SUDT. It didn't work well in my tractor and one of the problems was it foamed easily and took a long time to clear up. I did the same sort of test that you did. My hoe worked OK even with the foaming but the hydraulic pump developed a whine. Since the SUDT foamed so much I complained to the dealer and also wrote a letter to Kubota telling them about the foaming problem and asking them to check their oil themselves. Long story short: I never heard back from either one.

After not hearing any response for a couple of months I played a hunch and went back to using the New Holland Multi-G 134. That fixed my hydraulic problems.

BTW, my tractor came from the dealer with a mix of standard Kubota hydraulic oil and New Holland Multi-G-134. The Kubota oil simply because that is what was in it when new, and the G-134 because the mechanic spilled about half the original tranny/hydraulic oil when he changed the filter G-134 is what that particular Kubota shop carries as their bulk oil in drums, so that's what they put in mine. It worked fine for almost 200 hours until I decided I just had to try the SUDT.
rScotty

 

[TBarD]

Is there anyway to keep the m59 hydro oil from being infused with air? I think its a big problem of mine. My tractor starts off digging good but loses power after it is worked(still!) So I took a small sample of fluid after being used and put it in a clear plastic container. It was milky with air. After it set a couple of days it was normal looking, no air. So the foaming has to be bad. I am running the new synthetic Kubota fluid. Maybe change to new fluid?

A cloudy appearance could also indicate water contamination, however the symptoms you report sound more like air entrainment. You can test for water contamination by putting several drops on a hot plate; if water is present it will sizzle.

Possible causes of air getting to the system are 1) reservoir level too low (probably ruled out), 2) a leak in the suction line anywhere from the tank to the hydraulic pump, 3) a damaged return line with fluid pouring into the top of the reservoir instead of discharging below the top level. The first thing I would check for would be 2). All it would take is a pinhole to get air entering the system during operation. A small leak would result is air entrainment and spongy oil; a large leak could cause pump cavitation and eventual destruction of your hydraulic pump. If there is any sign of static leakage around the suction line (when the machine is turned off) that would indicate a possible problem. Conversely if oil is placed on a clean joint or connection in the suction line, and it disappears during operation, that would indicate a point where air could be drawn into the system.

 

[TBarD]

You might be thinking of the posts we had on that subject earlier. (posts #56 & #107...I think....)

At 200 hrs changed to SUDT. It didn't work well in my tractor and one of the problems was it foamed easily and took a long time to clear up. I did the same sort of test that you did. My hoe worked OK even with the foaming but the hydraulic pump developed a whine. Since the SUDT foamed so much I complained to the dealer and also wrote a letter to Kubota telling them about the foaming problem and asking them to check their oil themselves. Long story short: I never heard back from either one.

After not hearing any response for a couple of months I played a hunch and went back to using the New Holland Multi-G 134. That fixed my hydraulic problems.

BTW, my tractor came from the dealer with a mix of standard Kubota hydraulic oil and New Holland Multi-G-134. The Kubota oil simply because that is what was in it when new, and the G-134 because the mechanic spilled about half the original tranny/hydraulic oil when he changed the filter G-134 is what that particular Kubota shop carries as their bulk oil in drums, so that's what they put in mine. It worked fine for almost 200 hours until I decided I just had to try the SUDT.
rScotty

I don't question this, but I just wonder if there wasn't more going on here beyond just changing the type of oil used. It is hard to believe that the manufacturer specified oil would not work for the tractor, nor is hydraulic oil all that complicated, so there may be some other explanation. Probably any high quality oil that meets UDT or preferably SUDT specs would work. Changing the hydro oil and filters is a pretty significant change to the system. Perhaps in the second oil change something happened in the input (suction) line - a loose fitting or maybe the oil filter in the suction line had a small air leak at the O-ring? If so, just replacing the oil and filter with anything else within spec could very well have "fixed" the problem. A good test would be to go back to SUDT2 the next time you change out the hydro oil and see if the problems recur! (consider it for the benefit of science )

 

[Hersheyfarm]

A cloudy appearance could also indicate water contamination, however the symptoms you report sound more like air entrainment. You can test for water contamination by putting several drops on a hot plate; if water is present it will sizzle.

Possible causes of air getting to the system are 1) reservoir level too low (probably ruled out), 2) a leak in the suction line anywhere from the tank to the hydraulic pump, 3) a damaged return line with fluid pouring into the top of the reservoir instead of discharging below the top level. The first thing I would check for would be 2). All it would take is a pinhole to get air entering the system during operation. A small leak would result is air entrainment and spongy oil; a large leak could cause pump cavitation and eventual destruction of your hydraulic pump. If there is any sign of static leakage around the suction line (when the machine is turned off) that would indicate a possible problem. Conversely if oil is placed on a clean joint or connection in the suction line, and it disappears during operation, that would indicate a point where air could be drawn into the system.

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=277104"/>

I'm sure it's air,mill take a pic tomorrow and post. You would think with all the testing they did they would find it. The oil clears air after it sits, that makes sense that it starts off strong but gets slow. Thanks

 

[rScotty]

I don't question this, but I just wonder if there wasn't more going on here beyond just changing the type of oil used. It is hard to believe that the manufacturer specified oil would not work for the tractor, nor is hydraulic oil all that complicated, so there may be some other explanation. Probably any high quality oil that meets UDT or preferably SUDT specs would work. Changing the hydro oil and filters is a pretty significant change to the system. Perhaps in the second oil change something happened in the input (suction) line - a loose fitting or maybe the oil filter in the suction line had a small air leak at the O-ring? If so, just replacing the oil and filter with anything else within spec could very well have "fixed" the problem. A good test would be to go back to SUDT2 the next time you change out the hydro oil and see if the problems recur! (consider it for the benefit of science )

Yes, I can't disagree with what you are saying. In fact I completely agree. It makes sense that all hydraulic oils are basically similar and able to be mixed. After all, the tractor is designed to power hydraulic attachments.....and that means that whatever oil is already in the attachment will be mixed with the tractor's oil. Kubota's SUDT synthetic specs offered a slight improvement at low temperature and I thought of it as an upgrade so made the change.

Even as I filled it, I could see that the SUDT had entrained bubbles just from being poured in the funnel...and that they persisted longer than expected. As you say, there might be some other explanation for what I was seeing. For my part, I was more intrigued than concerned; just made a mental note of the fact and didn't think more about it until the louder pump noise began to bother me. In retrospect, it took me way too long to figure out that the oil itself might be the problem. And I still don't know that the oil was the reason. As you say, it could have been something else.

I didn't do any tests on my SUDT oil - just drained it into the original buckets and contacted Kubota. No response to that so far. I also don't know if Kubota makes or monitors that oil. The labels on my containers say that the country of origin is the US. It is date stamped Aug, 2008. A few months later after I got to wondering if the pump noise might be connected to the oil I went back to the dealer to ask for more information. I was told that Kubota no longer sold the SUDT. They had pulled it all and changed to a new formulation called SUDT2. That's when I decided to change back to the New Holland.
rScotty

 

[Hersheyfarm]

That is after changing front bucket to pallet forks, maybe ran it 15 min.

That is Sitting in jar for 1 hour. You can actually watch the bubbles coming to the top like carbonation. This has to be my problem.

 

[Hersheyfarm]

as of now i have smeared grease all over the pumps and suction lines, atleast all i could reach. this is what dealer said to do. no help. has anyone else ever noticed thier fluid when changing it? could this be normal for the M59? im trying to get it in the shop but absolutly need it every other day but will get it in befor 11/20 when warranty is up.

 

[TBarD]

as of now i have smeared grease all over the pumps and suction lines, atleast all i could reach. this is what dealer said to do. no help. has anyone else ever noticed thier fluid when changing it? could this be normal for the M59? im trying to get it in the shop but absolutly need it every other day but will get it in befor 11/20 when warranty is up.

The old fluid in mine was perfectly clear when I changed it out; looked the same as the new fluid (the filters however had picked up metal bits and definitely needed to be changed). But it had been sitting for a while so it is not a conclusive test. I haven't had a chance to draw some fluid out after having used it hard for a while, which would be the thing to do to check air entrainment. From your pictures and symptoms it definitely looks like this is your problem however. In addition to the suction lines and pumps, the filter for the suction line (one of the two on the right side) is also a potential source of the problem, as air could be drawn in if there were any leakage around the o-ring.

 

[rScotty]

as of now i have smeared grease all over the pumps and suction lines, atleast all i could reach. this is what dealer said to do. no help. has anyone else ever noticed thier fluid when changing it? could this be normal for the M59? im trying to get it in the shop but absolutly need it every other day but will get it in befor 11/20 when warranty is up.

Was your dealer being serious? Or just being cute? I hope you don't mind, but that mental image of you crawling around that smearing grease all over the tractor is definitely worth a grin.

I keep re-reading what TBarD wrote back on 8/16 and agree that it looks like air entrainment. No, I haven't checked my own M59. But my first reaction is that any air entrainment in a hydraulic systems is not right. But is that correct? Anyone know?

Here's an experiment that is lots less messy: Somehow extract or drain a quart or less of your hydraulic fluid into a mason jar and then buy a quart of some other brand hydraulic fluid and put in a similar jar. Now shake them both up good or see how the foaming compares. You might even get your dealer to sacrifice a $20 blender from BB&B to the cause....You gotta admit it sure would be nice if the foaming could be fixed so easily.

Hmmm.....I wonder if it's possible to get a sample by running a catheter-sized tube down the oil filling port and pulling some oil out with a big syringe? If you have livestock then things like catheters and syringes are probably in the barn there somewhere.
rscotty.

 

[Hersheyfarm]

Thats where I get my samples, from the oil fill. I use a fluid extractor that looks like the tail end of a grease gun and extended the clear tube on it with 3/8" pex. It reaches the bottom of sump. if my tractor is sitting and i draw some out it is clear. start it and let it run for 5 min and the oil is entrained. with 20-30gpm and such a small sump on these things maybe this is normal.

 

[rScotty]

OK, I pulled some samples from my own tractor yesterday. Temperature here is in the 70s, trans/hydraulic oil is New Holland Multi-G 134 with 100 hrs on it which included all new filters. Only hydraulic problem we have is a bit of whine from the high pressure pump (on engine right side) when the motor is cold.....which either goes away or gets so quiet I can no longer hear it as the machine warms up. This M59 rarely gets asked to do much hard work and definitely not quickly. It's babied.

I took a picture before starting the tractor and the oil is clear. Any haziness is simply whatever was last in that syringe.... The second sample is about ten minutes later after using the backhoe to lift and load a table saw into my buddy Craig's pickup. Altogether the M59 ran at idle for about ten minutes, moved the backhoe booms twice rather slowly, and drove about 50 feet in low gear.

We were flabbergasted at the amount of bubbles of entrained gas (air? oil vapor?) in the oil. Craig and I both know a bit about the physics of air and vapor entrainment in fluids....it would be interesting to know which type this is. Whichever it is, we were sure surprised to see it there. To make sure, I drew another sample and it was identical. The sample in the photo has been in the syringe less than a minute and looks to be already clearing - which is good? The next day the oil in the syringe had cleared up entirely. I don't know if that took minutes or hours.

The immediate question is whether this bubble entrainment is a also typical of other tractor hydraulic systems?? And would it clear up if the tractor ran longer?

rScotty

 

[Hersheyfarm]

well i guess i can clean all the grease off of my pumps and suction lines now. Ive checked mine after running hard for a while and its the same as it is when only running for a for a few.

 

[TBarD]

I am surprised by the amount of entrained air as well. This is not
foaming, it is entrained air (or other gas), i.e. small ~1mm bubbles of
air mixed in the oil. It looks excessive from the pictures, however I
do not know what is normal either. I will run another test myself when
I get a chance, but it probably won't be for a few weeks when I have the
tractor back to the garage.

Some amount of air entrainment in a warmed up system is probably normal.
Hydraulic oil at ambient temperature in an open system like we have will
contain 10-12% dissolved air by volume - this is when the oil is clear.
If we then heat the oil and pressurize it to 3K PSI in the lines then
depressurize when it returns to the reservoir, air bubbles can form as
the solubility of the oil is reduced. Air can also come out of solution
at the inlet due to decreased pressure in the suction, especially when
the system is cold, or if there is any clogging or other restrictions.

So a certain amount of entrained air in a warmed system is probably
normal. Excessive air entrainment likely indicates either an air leak
in the suction area, improper oil level at the air intake, or agitation
such as a splashing return which forcibly mixes air (this seems unlikely
in a properly designed system).

 

[Hersheyfarm]

I am running 1/4" above full right now to increase fluid volume in sump. I tried earlier to take a before and after sample from my mf4345 but my hose isn't long enough to reach the fluid in the sump, but I will. I expect it to be very violent in the sump of the m59 when it's running. Increased fluid volume may be needed.

 

[TBarD]

Another worrisome point here is running at 2700 rpm. None of the rest of us do that - when I am working it hard I run maybe 2200-2300 while wearing hearing protection (and it is hard to see that anything would be gained by running harder). You might run a test at these lower RPMs to see if the problem is unchanged. Any of the problems with flow restriction or fluid temperature, suction or agitation could be worse at max RPMs. If fluid temperatures exceed 140 or so I would be concerned, and it will tend to make air entrainment worse. Also fluid oxidation - your fluid when cool looks a bit colored, which would indicate oxidation due to excessive temperatures.

 

[dsgsr]

I fixed the problem with the Kubota oils. I use John Deere Low viscosity Hy guard, Been around for many yrs. and no problems. OH NO, JD blood in a Kubota it works just fine. OR you could go to Napa and buy 424 Hydro oil, Same thing Good quality.

David

 

[Hersheyfarm]

Another worrisome point here is running at 2700 rpm. None of the rest of us do that - when I am working it hard I run maybe 2200-2300 while wearing hearing protection (and it is hard to see that anything would be gained by running harder). You might run a test at these lower RPMs to see if the problem is unchanged. Any of the problems with flow restriction or fluid temperature, suction or agitation could be worse at max RPMs. If fluid temperatures exceed 140 or so I would be concerned, and it will tend to make air entrainment worse. Also fluid oxidation - your fluid when cool looks a bit colored, which would indicate oxidation due to excessive temperatures.

Kubota said to run at full rpm, mainly for heat dissipation, and running at full rpm's gives you their rated flow to work a couple of cylinders at a time with now slow down. Digging an 8' deep sewer at half rpm is crazy slow. Even your manual says the backhoe works best at tractors rated rpms. Kubota also assured me these machines are engineered to run full rpms all day long. Heres something else that will upset you, kubota is ok with 180+ degrees in the fluid temps. seems high but they should know.They advertise this machine as an industrial replacement for a full size TLB. This is straight from kubotas service tech, not the dealer.

The foamy fluid happens with just 5 min of warm up time, and is there after running hard. Ive checked it several times.

 

[Hersheyfarm]

I fixed the problem with the Kubota oils. I use John Deere Low viscosity Hy guard, Been around for many yrs. and no problems. OH NO, JD blood in a Kubota it works just fine. OR you could go to Napa and buy 424 Hydro oil, Same thing Good quality.

David

could you check your fluid for air after warm up for us? I could care less what brand I use just want the hydraulics to not fail again after warranty.

 

[rScotty]

Kubota said to run at full rpm, mainly for heat dissipation, and running at full rpm's gives you their rated flow to work a couple of cylinders at a time with now slow down. Digging an 8' deep sewer at half rpm is crazy slow. Even your manual says the backhoe works best at tractors rated rpms. Kubota also assured me these machines are engineered to run full rpms all day long. Heres something else that will upset you, kubota is ok with 180+ degrees in the fluid temps. seems high but they should know.They advertise this machine as an industrial replacement for a full size TLB. This is straight from kubotas service tech, not the dealer.

I share the same concerns about the high RPM that TbarD mentioned. I cannot tell from reading whether Kubota is saying that one should run at max RPM....or merely that one can. I agree that they do say in several places that the machine is capable of working at full RPM. Although they moderate that in the technical publication where the caution about exceeding an oil fluid temperature of 140F. So temperature rather than the RPM may be the limit.

Running at full speed in order to increase heat dissipation is an unusual argument to say the least! I'm betting that one didn't come from their technical staff. Frankly if someone told me that I'd sure take it with a large dose of salt.....better make that a 50lb block with trace minerals....

BTW, I didn't know that fact about hydraulic oil normally containing such a high percentage of dissolved air that TbarD mentioned. If so, then far less than ten percent of dissolved air by volume - coupled with an increase in temperature and varying pressure - is more than enough to create the entrained gas that we see in the samples. And if that is so, it is probably inevitable in any open hydraulic system (some JDs and some industrial equipment use a closed hydraulic system) That means that the entrainment we are seeing is not additional air from splashing, it would simply be an increase in bubble size due to the change in temperature and pressure. In fact, the entrainment would be made to look much worse by the simple act of using a syringe to take a sample....like I did...and that's something I think we all did.
Luck, rScotty

 

[rScotty]

......... Digging an 8' deep sewer at half rpm is crazy slow.

I'm glad you said that. The technical stuff is fun, but it boils down to your needing your backhoe to move faster. That makes sense. Have you timed the cycle times on yours? That might answer all the questions. And for warranty issues timing it would be definite and repeatable. Somebody suggested doing that a while back. Sorry, but I forgot who it was. Anyway it sounded good so I took a stopwatch along with my M59 Kubota manual and timed the various loader and BH cycle times on ours. It was sort of surprising how closely it matched the published specs.

Normally I run at about 2/3 rated speed and less than that for light work. At full rated RPM it feels less efficient because of the boom speed. Of course the problem might be with me rather than the BH, but in my hands it sure slams and throws things around.

Regardless of the RPM, The M59 controls don't seem to allow the BH bucket to move in all directions at once. If it could do all motions simultaneously that would certainly speed up the BH work. Some industrial machines have that ability and I miss it.
rScotty