Backhoe Side to Side -- Stuck?

[rScotty]

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.

I'm not even sure that hydraulic cooler has a specific output. Can you tell?? I just cannot tell from Kubota's schematic. Does the flow through the cooler depend on whether the power steering is being used??

I thought I could tell by the temperature difference too. But so far I only get a couple of degrees difference, and that could be due to anything...probably heat transfer through the mastic. I'm thinking I may instrument the backhoe separately just to see if it is different. It's cheap enough to do.

Ultimately I'd like to be able to say that fluid temperature is or is not related to whatever causes some of the Kubota TLB backhoes to have an occasional problem with their swing power. tr

Depending on who you believe, the real problem with tractor high temperature hydraulics is that trans/hydraulic fluid ages faster - loses shear-resisting lubricity additives - at high temperatures. That hi-temp aging is one reason why pure hydraulic fluid is often made with alcohols or something other than a petrochemical oil base. If you know of any good technical articles on trans/hydraulic fluids I'd be interested.

I don't know much about the state of IR gun technology. I haven't tried an IR gun since about 5 years ago when I bought several and tested them. At the time, they were not even close to what I measured with a contact type thermister. The guns were not repeatable on metal, and slightly better on non-metal surfaces - but not good enough for absolute temperature. Maybe since then the IR guns have solved their emissivity/reflection problem - or whatever their problem was.
rScotty

 

[Smokeydog]

Understand getting good representative temperature measurement. All methods required some technique. Do like magnetic simple bimetal coil thermometers for things like motors, metal pipe or cylinders in the temperature range we are dealing with.

Oil break down, water emulsion, age all reasons to evaluate higher temps and determine maintenance schedules. Don’t have good comprehensive literature just bits and pieces gleaned from experience. Do believe preventative maintenance does pay rewards in the long run. Thinking the Kubota maintenance schedule are conservative for my hobby use. Buy my equipment is used so I’m operating in the long run long run lifespan.

Now you have a mechanism to read temperatures and could see how driving around compares to backhoe operations. We will have you looking more like a space shuttle than tractor soon.

 

[TWD]

I want to update that mine has had issues again and every-time I open up to check the pin is stuck.

I originally cleaned it, so I thought... but this time I ran it for hours in my ultra-sonic cleaner at a higher temp and it came out MUCH cleaner. I'm not sure if the overheat hydraulic system "baked it" with mm or so of black gunk but when that is stuck it doesn't work as expected, with it free moving it works 100% fine. I popped off all the gaskets off and ultra-sonic cleaned EVERYTHING in carb\engine safe cleaner (made for ultrasonic cleaner).

I think this may be a combination issue:

1) 100% from pin getting stuck
2) pin gets stuck from hydraulic fluid baking on the pin making it not move smoothly
3) hydraulic fluid baking on the pin is from over-heating the fluid, or, possibly just running it very hot (within spec) for long-periods of time. Not necessarily running at high rpm for long periods but running it very hot (ie: hard use)

I've yet to find any contaminants in my fluid like others have mentioned finding little pieces of something.

Since I've been able to fix mine at least 4 times now by cleaning that pin (before this deep-clean) I'm rather sure I've isolated the problem to the valve\pin and the heat.

 

[Smokeydog]

Nice follow up report.

 

[TWD]

Thanks! The only thing left I might do is add an extra hydraulic cooler... I need to read up on how the current one works.

I'm wondering if maybe the backhoe return fluid is avoiding the cooler and dumping back into the tank which is why when using the backhoe for 3+ hours it gets VERY HOT even if the cooler is clean. It would be easy enough to add one between the return QC and the backhoe, and mount it somewhere flat underside, with a skid\protection.... just not sure that's worth it, nor what pressure the return line is yet.

My 15g capacity log splitter fluid overheats too after ~6hrs of continued use and starts spewing fluid from expansion, I plan to add a cooler to that too.

Needing to add coolers to all my hydraulic systems... makes me think we may be hitting the wall of consumer\construction equipment by running it for so many hours at once, and in non-cool weather. I doubt commercial or industrial equipment has this problem considering they're often used multiple shifts per-day.

 

[Smokeydog]

Interesting. rScotty was getting some temperature differential data on the hydraulic cooler. Better? Bigger? or electric fan cooled? Maybe monitor backhoe supply and return? Upper valve block temperature?

The hot fluid from the cylinders which goes thru the valves is too hot? The tractor hydraulic cooling may not be the only problem.

Weld some cooling fins on the cylinders? Sometimes see some interesting aluminum extrusions at the scrapyard that could be hose clamped to the cylinders.

Maybe adjust technique by exercising the cylinders periodically with no load, full extension/retraction to circulate fluid to remove heat.

Maybe a small electric fan to ventilate the backhoe valve block control pedestal?

I’m sure excavators take credit for their large cylinders for heat removal.

I find age helps limit my tractors overheating issues. Picking cooler weather and shorter shifts.

Wonder too if the black coating could come from inside aging hydraulic hose?

Had a M5030 that would lose power steering. Had a fine stainless steel filter in the pump reservoir. Looked clean. Rinse with brake cleaner would remove considerable black coating restoring power steering.

 

[M59]

TWD

Did you buy the machine new or used?
How many hours are on your machine and how many hours since ALL 3 hydraulic filters and hydraulic fluid replaced?
Has anybody added or "fixed" a leaking hose or connection anywhere in the hydraulic system and possibly contaminated system with dirt, metal particles, or teflon tape? The dark material may indicate you have fluid breakdown due to age, contamination with moisture, incompatible mixture of different hydraulic fluids.

I've also experienced the hoe improper operation after purchasing a 230 hour/ 5 year old machine used M59. First was failure to swing left or right if immediately asked to do so upon machine startup but after machine ran 5 minutes then swing operated properly. Second would be running backhoe for several hours and upon getting machine ready for storage in shed the swing operation would fail on left or right motion. Third was inability to grasp anything, with any degree of force, between hydraulic thumb and bucket because thumb would easily push bucket around. Originally ruled out low fluid and then discovered dirt stuck in relief valve on bucket curl cylinder causing valve to relieve any pressure that thumb placed on curl cylinder. Finally took machine, with 1100 total hours, to local Kubota dealer with mechanic who was old, crotchety, had gray hair, greasy hands, and lots of knowledge spanning many different tractor, skidsteer, excavator , etc manufacturers. He determined that all three hydraulic filters were factory original installation and were seriously plugged, therefore cold hydraulic fluid ( issue #1) flowed slowly thru filters until warmed by pump then swing would function. He dumped dirty fluid, flushed system, and refilled with clean hydraulic fluid.

I'v had no issues with backhoe hydraulic controls, now with more than 1000 additional work hours, since fluid and filters changed even after digging all day to the point where I can not hold my hand on the cylinder attached to boom and dipper stick due to very high temp. I've not measured boom cylinder but its at least 120-130'F. I'm thinking you have dirt in the hoe hydraulic fluid that may not be making it back to the reservoir and this is causing you sporadic problems. The valve stack on the backhoe is serviced by 2 pumps that add flow from opposite ends of the valve pack with one of pumps being dedicated to providing flow specifically to the swing control valve located at far left ( when sitting in hoe operator seat). Since these valves are all power beyond then any excess flow/ pressure is available to valves that are being operated. This allows multiple operations of swing, boom and dipper movement, and bucket curl to occur at same time but also may allow dirt to circulate within valve pack or between valve pack hydraulic cylinders without making it back to reservoir.