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Discussion Starter · #21 ·
I'll suggest to disconnect power steering supply line then cap pressure line & operate tractor with PS disabled to see if hyd oil is cooler while harvesting hay .
I can try to disconnect and see what happens. Is it possible though that the steering column is hot just because the oil is hot? I mean the oil is circulating through, so it makes sense to me that it could be coming from anywhere, because all the hydraulic components are extremely hot.


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Technically hyd oil should stop at steering valve when steering wheel isn't moving & only proceed when steering wheel is turning. Closed center hyd system is designed for oil to STOP at control valve until control valve is opened allowing hyd oil to proceed. Probably a high pressure internal leak is causing oil to heat.
 

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One thing I'd do when you are done fiddling with hay is, pull the injectors and do a compression test. Willing to bet you have weak or glazed rings and possible valve issues as well. Was the overhead ever adjusted or do you even know?
 

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One thing I'd do when you are done fiddling with hay is, pull the injectors and do a compression test. Willing to bet you have weak or glazed rings and possible valve issues as well. Was the overhead ever adjusted or do you even know?
It would surprise me with 1500 hrs of use that engine would have a compression problem unless someone has been overdosing engine with starter fluid. I strongly advise to check inj pump timing.
 

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Could be a number of issues but white smoke when operating is indicative of something wrong and of course the owner don't know the history of the tractor and how it was used / abused either. He said it was hard starting. Diesels need compression to fire and atomized fuel at the right time so something is wrong mechanically.
 

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I sold New JD 2840 tractors & they were hard starting more due to hyd pump not going into de-stroke mode than due to engine problems. The ""something wrong with diesel engine smoking"" could be as simple as Injection Pump not timed correctly not something to do with compression!!!
 

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Your Kubota has open center hyd's with no need for a destroking screw. JD 2840 has closed center hyd's that was designed to de-stroke automatically when there was no demand for extra hyd pressure BUT when internal hyd leaks rear their ugly head this ceases. When CC hyd pump loses it's capability to de-stroke & drag on starter is increased one needs to manually or electronically de-stroke the CC hyd pump as an engine starting aid.
 

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Interesting, thanks. I'm not well versed in how hydraulics work and if I had an issue, I'd call my dealer for advise.

I do have something going on with the open station and was going to post it up anyway, but I'll ask here, maybe you can tell me...

The OS (6000 hours) has developed a whine in the hydraulic system, not there constantly, comes and goes and if I put my hand on the hard line that comes off the pump, I can feel it vibrate. I can also hear it under the dash so I'm thinking it might be time to rebuild the orbital steering pump. Steering is not impacted at all and no leaks anywhere, in fact the entire tractor is leak free.

I don't like the whine. Maybe it's time for a trip to the dealer and have Dennis rebuild the orbital steering unit and yes I have the WSM. No issues with fluid temperature either. gets warm, never hot and the oil cooler is clean. Fluid isn't low either. Right at the top of the dip stick (15 gallons) and I just changed it and the filters in the spring.

Opinion?
 

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My guess is rebuilding steering valve possibly wouldn't solve the whine but your technician would have better knowledge. How many hrs of use since hyd filters were changed probably not very many? The majority of my hyd experience is with closed not open-center systems.
 

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Full service this spring including both high and low pressure filters (Kubota of course) and 15 gallons of Chevron YHC synthetic All Weather fluid.

I don't have the service history on this one because I bought it used from of all things a JD dealer and not local either. Had them deliver it to the farm before my dealer fetched it from here. While it was here, I changed all the fluids, the case appeared to have Hy Guard in it, it was half full and filthy, the motor oil was black and interestingly, it appeared to have the original fuel filter on it, even my dealer was amazed that it even ran. Kubota paints their filters at the factory grey and it was grey. Had the dealer address all the issues and repair them. That was 2 years ago. really don't get worked hard. Just does the raking and rarely has the chopper (batwing) attached.

Just started making the whine sound this spring. It is a 2002 and it has a fair amount of hours (6000) so I have fully expected some issues to arise. Runs very well and is very frugal on diesel, runs clean, no smoke and like I said, I rarely get it up on boost.

Dennis put it on the dyno at the shop and it dyno'd at 95 pto which is a bit more than what the stock number is. I think stock power is around 85.

Thinking this winter, it's off to the dealer and have Dennis diagnose and repair it. I've read the steering orbital motor is a hard rebuild and a reman is expensive.

The other one has to go in as well. Bought a new Kneverland round bailer (full electronics) and the electronic package that is in it now has to come out and be replaced.

One difference between this one and my other one is, if I don't 'glow' this one a bit (no matter what the ambient is), it will start and stall once. My other one don't do that at all. As hot as it is, the other one dead cranks and pops right off.

Like I said, have no clue about it's previous life and what abuse it had. I'm sure it was by the looks of the bucket that came with it. Was told it was on a dairy farm. probably spent it's life piling manure. The air filter element was solid with filth. Even the inner was filthy. All replaced with new.

Other than the cab, they are identical, 2 speed pto's, creep gears, cast centers and triple outlets on the back but this one has the optional down exhaust, the other one is through the hood. Kind of like the down pipe as it don't obstruct your forward vision.

Needs new shoes too. In fact both need new shoes. Putting that off as new shoes will be over 10 grand for the pair.
 

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Discussion Starter · #32 ·
I don’t see this (my issue) stemming from engine problems. I have no problems starting until temps get down to freezing. And especially after I hosed the heat exchangers out, engine coolant temp stays below halfway on the gauge.

So maybe someone can answer me this.
Why does an internal leak or the oil getting hot send the pump into a destroke? That sounds like what’s happening to me after 3-4 hours. Lines chatter and I slowly lose all hydraulics until I shut down and let it sit for an hour.


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Trans pump only has a certain amount of GPM of oil it can pump. Once internal leak exceeds a large portion of trans pump GPM then frt pump starves for oil supply then starts cavitation. Closed center frt pump has no ability to suck oil IE it must have oil furnished therefore the need for a charge(trans) pump. Higher temp oil creates a larger internal GPM leak.
 

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Discussion Starter · #34 ·
So what's the procedure for starting to trace internal leaks?

Hoping this isn't the infamous cracked internal line, but even if it is, what will keep the replacement from doing the same thing?

Anyone have any good reads on this issue?
 

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Have you looked inside open hyd filler hole for moving oil when 3 pt is fully raised & engine is running? Does this tractor have a FEL? Best tools for hyd diagnostics are a flow-rater, 5000# & 300# gauges. There should be many threads on the WWW about diagnosing/repairing JD closed center hyd systems
 

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Discussion Starter · #36 ·
So it’s been awhile, but here’s an update.

Engine running, 3-point raised or lowered, I see no oil through the filler hole.

I took the loader off to access the lines and valve easier. I also plowed up and am going to reseed 2 acres, and didn’t need the loader. Noticed that even though I was working the tractor hard and engine coolant temp was warm, I never had the hydraulics act up. In the hay field, after running for 3 hours or so the hyd oil would get VERY hot, and I could not operate anything hydraulics. During plowing for 4 hours, steering shaft was still cool.

So here is my two thoughts.
1. Taking the loader off and no longer having a leaking FEL valve solved the issue. Currently working on getting the valve off and resealing.
2. Hay season problems occurred at 90-95 degrees. Last week I was plowing in 60 degree sunshine. Maybe it was cool enough that it couldn’t get hot.

Thoughts?
 

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What type valve was utilized to control frt end loader? Sounds as if it wasn't designed for 2840 closed center hyd system or the internal seal on closed center conversion plug has failed OR pressure relief valve on FEL control valve if applicable isn't set to stay seated at 2250+ psi.
 

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Discussion Starter · #38 ·
i think your FEL control valve is a Cessna brand. If my guess is correct valve seal kit is shown in photo below. Some older style fuel lift pump had glass bowl that was upside down when pump was mounted on engine.
Guess this is what you’re asking. Just got it pulled off, and I don’t see a name brand. Just numbers. JD 148 loader that is supplied from the block under right side platform. Lines continue up front. Return from loader goes straight to filter housing.


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Simple test with hyd pressure or compressed air applied to FEL valve "in port" with valve control lever(s) in neutral. IF when pressure is applied to in port a large volume of oil/air exits valve "return port" then valve spool to housing clearance is too much or if applicable control valve relief valve isn't holding system pressure or closed center conversion plug if applicable has failed
 

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Discussion Starter · #40 ·
Really irritated now. Resealed the valve, and noticed nothing glaringly obvious wrong. O-rings were a little brittle, but not bad. Spool looked OK.

Put loader back on and there is no difference. Guess I should have ran the tests with the valve still off.

Previous owner told me that the loader cylinders had just been repacked, but it seems like he lied about other things so who know if that’s true. Seems like my only options are remove valve again and see if Tx Jim’s test reveal anything, or repack the loader cylinders.


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