Backhoe Side to Side -- Stuck?

[rScotty]

I should have updated this a month ago or more now...

I took apart the entire thing as someone pictured (thank you so much), ran the springs\misc parts through my ultrasonic cleaner, re-assembled, and it works... mostly.

However... I still do not have full pressure to one side... for example I can't use the backhoe to lift the rear end over a ditch in one direction, but I can the other direction with so much force I'd throw myself out if not paying attention or running to high RPM when doing so

I've put about 60hrs on the backhoe since then 100% use of removing stumps and now my thumb cylinder is leaking around the cylinder rod (already replaced on my dipper), and in addition to that my main cylinder is leaking around the threads... hoping that's just needing to be tightened up but it's a bit upsetting to see so much issues in something that was barely used for years until now. (It was used to lift and move things monthly since I've owned it, and remove a stump or 2, but now I'm using it for hours on end.)


Question -- For those of us who had this problem do you operate the backhoe for hours on end and\or in high temperatures? I noticed I was getting really hot when outside air temp was only 70-75 and it was from the AUX hydraulic lines to the left (not in use) radiating heat... I cleaned out my hydraulic cooler fins and ran it for 2-3hrs and the AUX lines never got hot that I felt them!! That was nice. Does Kubota have an "overheat" hydrlauic fluid warning? Or how do you know it's overheating? (I personally can tell after 2-3hrs I start to smell the fluid, not burn, its just "its heated up now I smell it.) I'm just curious if i'll know (alarm) if I overheat it, or if not, and if not, I'll change all fluids.

Keep up the good Science! We are slowly accumulating information. We will figure this out someday; I've no doubt. And it is fun to be able to work on something that is so technical that
Kubota couldn't make any progress on it.
To answer your question... Yes, I have noticed that the swing function does change at high temperatures. After hours of operation there is sometimes a little change in how the swing responds to the lever command - particularly at the very extreme of the swing. It occurs as a slight hesitation between the lever movement and the swing movement. Normally they are simultaneous. I see this on the left swing more than the right, but that might just be because I use that side for small movements and so it is more obvious.

I don't know if there is a hydaulic fluid heat warning. The JD310 has a converter temperature gauge, but not the M59.

One thing I have encountered from reading & study is the idea that that trans/hydraulc fluid differs from motor oil in how it ages with temperature. That seems to be common knowledge, but just how and how much is harder info to find.

Some literature mentioned that only a very few high temperature excursions might drastically reduce the lubricity. However, the aging was said to be very much non-linear and I haven't seem any real data.

I may go clean off those radiators today and maybe put some temperature gauges on the hydraulic lines. Will keep us posted.
rScotty

 

[Zork]

Try switching out the cylinders with each side and see if your problem changes with the cylinder. That should indicate that fluid is leaking past the packing when it's hot.

 

[rScotty]

Snip

I may go clean off those radiators today and maybe put some temperature gauges on the hydraulic lines. Will keep us posted.
rScotty

Today I cleaned the radiator cooling fins for engine and hydraulics. It was about like I expected, having not cleaned them in about 12 years or more. Anyway, just for fun info I also installed a gauge to compare hydraulic fluid temperatures entering and leaving the fluid cooling radiator. The temperature senders are external. The senders are just taped to the hoses after being coated with thermal mastic and insulation. Be interesting to see if this simple approach tells us anything.

I've got some BH digging to do next week, so that will give the gauge a workout.
Normally, most of my backhoe work is picky rock wall construction done at just above idle - and I may mess with a series of footlocker size rocks for an hour before satisfied with how they fit. When doing that type work there is not a lot of backhoe motion or high flow rates. But the work is constant and the sun hot. Even with that light work I can feel heat from the backhoe. When I park it, the main boom cylinder is uncomfortable to hold onto, but ok just to touch.
rScotty

 

[TWD]

Today I cleaned the radiator cooling fins for engine and hydraulics. It was about like I expected, having not cleaned them in about 12 years or more. Anyway, just for fun info I also installed a gauge to compare hydraulic fluid temperatures entering and leaving the fluid cooling radiator. The temperature senders are external. The senders are just taped to the hoses after being coated with thermal mastic and insulation. Be interesting to see if this simple approach tells us anything.

I've got some BH digging to do next week, so that will give the gauge a workout.
Normally, most of my backhoe work is picky rock wall construction done at just above idle - and I may mess with a series of footlocker size rocks for an hour before satisfied with how they fit. When doing that type work there is not a lot of backhoe motion or high flow rates. But the work is constant and the sun hot. Even with that light work I can feel heat from the backhoe. When I park it, the main boom cylinder is uncomfortable to hold onto, but ok just to touch.
rScotty

View attachment 883581View attachment 883582View attachment 883583

Yeah, that's my usual workload the last 13 or so years, only in the last 2 or 3 have I really started digging with it or playing logger moving large\heavy logs.

Can you link to that 2 probe temp device? I want to rig up something like that as well... I have a new cooler here too, just not sure how\where I would plumb it for additional cooling, but it sure seems like when working the backhoe (or even FEL) it's needed... the FEL cylinders get so hot you can't touch them just moving dirt after a couple hours of non-stop use.

Sounds like I'll be changing my fluid with the filters this year just to be sure all fresh after all the new leaks, and issues that popped up after heavy use of the backhoe.

 

[Smokeydog]

Today I cleaned the radiator cooling fins for engine and hydraulics. It was about like I expected, having not cleaned them in about 12 years or more. Anyway, just for fun info I also installed a gauge to compare hydraulic fluid temperatures entering and leaving the fluid cooling radiator. The temperature senders are external. The senders are just taped to the hoses after being coated with thermal mastic and insulation. Be interesting to see if this simple approach tells us anything.

I've got some BH digging to do next week, so that will give the gauge a workout.
Normally, most of my backhoe work is picky rock wall construction done at just above idle - and I may mess with a series of footlocker size rocks for an hour before satisfied with how they fit. When doing that type work there is not a lot of backhoe motion or high flow rates. But the work is constant and the sun hot. Even with that light work I can feel heat from the backhoe. When I park it, the main boom cylinder is uncomfortable to hold onto, but ok just to touch.
rScotty

View attachment 883581View attachment 883582View attachment 883583

That would be a good test. When mowing I have clear the radiators and screen several times a season. Curious what temperatures might be seeing. That’s usually the hottest I see the tractor.

Backhoe boom cylinder can get hot. About 180-190 degrees per millwright hand test.

 

[rScotty]

I ran the hoe today for about an at our normal BachHoe RPM for tricky work... around 1200/1500 RPM. We were digging up pipes that I didn't want to hit. Air temperature here was about normal summertime....roughly 80*F in the shade, and much, much hotter at 7000 feet in dorect sumlight.
Checking the fluid temperature after an hour of easy digging, the fluid entering the fluid coolant radiator was 122*F and exit temperature 111*F.

Here is the temperature guage I used. Interesting fact: the US-made plastic tape that I used to mount the sensors was bought at Ace Hardware where two rolls of tape cost about the same as the complete thermocouple gauge built in China, sold on Amazon, and shipped to my doorstep.
rScotty

 

[Smokeydog]

Like your experiment. Impressed how clean and new looking your tractor is. Mine was battle worn before I got it and have added a few scars. Think my heat exchanger is bare aluminum, not painted (2014).

To try to replicate your results, what heatsink mastic did you use?

On your heat exchanger one side has band hose clamps, the other has wire. Was this from a repair? Which side is inlet/outlet?

Haven’t figured out the mounting the instrument case in my application yet. Need to read real time from the operator position while bushhogging, tree cutting and carrying. Blank center console area probably the obvious spot. Longer leads necessary. Might have to go your route in China instrumentation as my Fluke thermometer cost >$10X and don’t want to trash it. Thermocouple readings on radiator, engine oil, hydraulic filter(s), under hood would all be interesting. Beginning to look like a science experiment from my past job. Then trying to improve heat transfer with fans and or additional exchangers could be better measured.

 

[Zork]

My tractor and backhoe does not have an oil cooler and a few times early on during heavy use I could smell warm oil. My transmission is gear and not hydro. For those of you with a cooler and elevated temps, can you install a remote unit in the return line with a fan in the open space at/below/between at the backhoe 3pt, or subframe connection?

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[rScotty]

Like your experiment. Impressed how clean and new looking your tractor is. Mine was battle worn before I got it and have added a few scars. Think my heat exchanger is bare aluminum, not painted (2014).

To try to replicate your results, what heatsink mastic did you use?

On your heat exchanger one side has band hose clamps, the other has wire. Was this from a repair? Which side is inlet/outlet?

Haven’t figured out the mounting the instrument case in my application yet. Need to read real time from the operator position while bushhogging, tree cutting and carrying. Blank center console area probably the obvious spot. Longer leads necessary. Might have to go your route in China instrumentation as my Fluke thermometer cost >$10X and don’t want to trash it. Thermocouple readings on radiator, engine oil, hydraulic filter(s), under hood would all be interesting. Beginning to look like a science experiment from my past job. Then trying to improve heat transfer with fans and or additional exchangers could be better measured.

I've no idea what's in my old box labeled as 3M Thermal Mastic. It feels grease-based. If so my guess is that it is pre-silicon and probably for low temp AC in my old '72 Chevy PU rather than hi temp tractor hydraulics. I used only the slightest amount because I was concerned that any mastic leakage would saturate my 1/8 " think insulation layer on top of the heat sensor bead. The heat sensing bead is tiny - about 0.050" diameter. To prevent seepage I separated the insulation from the bead & mastic with two layers of silicon and vinyl.
Doing it again, I would use a RTV type of mastic that cures flexible. Or none at all.

You've a good eye on the hose clamps. I didn't even notice the difference until you pointed it out. My excuse is I was racing the dark..... This M59 is one of the early ones and the system is all stock, so I looked in the M59 Parts Manual and sure enough they show hose clamps on the left side - which the parts book says is the O/C return line. And on the other side - labeled in the book as the HST return side - they show double wire band clamps. Yes, that's right: both lines are labeled as returns for different hydraulic circuits. I'm mystified.

The Shop Manual is not much help to me. Either the section that covers the oil cooling radiator is poorly written or I am missing something. I wonder if the M62 Shop Manual is any better?
My guess is the person writing it did not fully understand how the cooling functioned. Either that, or the cooling was added afterwards. The latter is a distinct possibility.

Looking at the hydraulic schematic, my perception is that the oil cooler does not cool all of the hydraulic oil flow that is circulating. It looks to cool a percentage in a bypass system working with the power steering circuit.

It might be worth instrumenting some other point than the stock oil cooler.
rScotty

 

[Smokeydog]

I would think lower temperature probe would identify the outlet. I wasn’t exactly sure which side either.

Thinking temperature under 200F normal. Maybe even 240F. People are poor thermometers so your data is way better. Spot checking backhoe boom and FEL lift cylinders with non contact IR thermometer could add reference data. There is value in information. I know enough to be humbled by my ignorance.

The first gen B20 had a flat plate hydraulic oil cooler in front of the radiator. Newer B26 uses just convoluted metal tubing.

Hot smell of hydraulics is a symptom of air entrainment usually on suction side. Any external leaks can also leak air and contamination back into a hydraulic system. Unwanted air in any hydraulic system causes overheating and poor performance. People concerned about running hot should troubleshoot the easy stuff first.

All the backhoes I have run have got hot with heavy use. Smaller ones you tend to be closer to the cylinders.