M6800SDT 4WD CAB - Engine oil Problem

JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
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New Market, AL, USA
See post #37 above. Tracking responses on a small screen you may be missing the feedback being offered ?
Thank you, sorry about that.
I will check the rest of the pump.

I never had a log splitter on it. Just the loader and a small 5 ft rotary cutter.

The loader is a LA1002-68C with the B00104 control valve. I could not see a relief valve in the diagram, I will post next.
Looking at the relief valve above PTO it looks like it has not been touched from Factory. Paint on adjusting screw and nut has zero marks on it.
Just a quick look.


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North Idaho Wolfman

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I personally would tear down the relief valves (tractor and loader), and the pump and inspect everything.

Get yourself a pressure gauge for testing system upon reassembly, to make sure everything is set and working properly.

Here is the loader relief valve:

 

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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
Update....
I disassembled pump, I could not see any damage. The seals and orings looked fine, pump gears turned freely and look good. Maybe there is something I could not see with inexperienced eyes.
However, with that said, I reassembled and installed new shaft seal. I bought a hydraulic gauge and couplings for loader and rear remote valve on top of PTO.
I was going to test relief valves, but I do not have any hydraulics.
I started the tractor after installing pump, remembering about the vent I loosened engine oil fill cap and oil and lots of air was spraying out. I put cap on and pulled dipstick loose and oil was spraying out of it. Not sure what normal is, figured I'd ask here. I pulled hose from vent on top of head cover and nothing coming out. The hose from intake has a slight suction, but the vent valve has no air coming out.
So a couple things.
Will my hydraulics come back if I run it at higher rpms? (Didn't want to do damage running them without full fluid flow)
Is the vent possibly the root cause of my problem?
Should oil be spraying out dipstick at 500-800 rpms?

I have ordered pump seal kits, new vent valve assembly, and hydraulic and engine oil filters, I figured I would change the filters and oils after I ran it a little. they will take a 5-7 days.




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rbargeron

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Sounds like there may be more blow-by than normal. Hard to say from this distance. Some engines do make more crankcase air than others.

On how much oil should spray out of dip stick hole, a running engine will toss oil droplets at the hole but it shouldn't be a steady stream.

No need to rev up the engine - just let it idle for a while giving the air a chance to work itself out of the filters. Check trans oil is full. Does the power steering work at all yet? It may start jerky but clear up as the air gets out. If the loader is connected hydraulic oil should start to flow after a couple minutes.

Wonder if the breather assembly on the head cover is functioning - looks easy to take off and inspect?
 

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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
It seems to be a steady spray of oil and air, I can post a video in a few.
I let the engine idle for about a min and nothing for hydraulics. I have changed oil and filters a few times and don't remember it taking this long.
I will post some video.

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North Idaho Wolfman

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You have a engine venting issue!
I'll have to do some research, but it sounds like you have a PCV valve that is plugged.
 

JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
Does it make sense that, I could have suction issue with pump and running it without oil (talking about original pump replacement), coupled with a positive crank case pressure caused the front shaft seal to blow and therefore the hydraulics were running on engine oil until a good flow started. Once the pump was primed it have enough pressure differential to continue the flow of hydraulic and engine oil?
I know it seems crazy.

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rbargeron

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In your first picture the seal looks like it blew out - it failed from pressure behind it. Crank case pressure would be going the other way.

In the second picture of the seal, the ID looks severely ripped and displaced. Was it found in that condition? did some of the ripping happen getting it out?

In any event the crank case pressure should never get high enough to do that kind of damage - something else would fail first (the rear main crank seal would leak into the clutch housing.)

Several things are pointing to too much pressure - both in the crank case and in the hydraulic system - (except for right now when it apparently won't do either.)

I think you need to find a local tractor hydraulics person with long experience who can patiently help examine the tractor and go through all the history with you, isolating and understanding the several conflicting developments, and finding answers that hold up.
 
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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
This was as found condition. It did appear to be blown outward.
What I don't get is why it was sucking engine oil in. I'm not sure why hydraulics are not working after replacing seal. I am on my way to the house right now, so I am going to post a few videos.

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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
Also, my hydraulic pump appears to be bad, I'm going to have to rebuild it. I ordered all the seal kit and orings for a complete rebuild.
Any advice, I had the pump apart and it doesn't look too complicated, but nothing beats a little experience.
I also will be removing the relief valves on the loader and pto. I ordered all new orings.
What should I look for aside from anything broken.

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North Idaho Wolfman

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Yea that's not right at all.

And just to confirm that was with the oil set at the proper level too right?

Pull the line off in yellow ad check for air flow out of the engine, if none then you have an issue with the PVC valve (in red).

 

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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
Thanks Wolfman, I ordered the complete assembly for breather valve.
I am discouraged, and at the same time thankful for the education. I think I'm going to nickname this tractor "perfect storm". I believe I am dealing with 2 separate issues.
The hydraulic issue I believe is related to the overpressure situation caused by one of the relief valves, which is why I was blowing hoses in my loader right after pump replacement. When there were no more weak hoses, the pump over pressured and blew out the chamber seals and shaft seal in hydraulic pump. I say this because after replacing shaft seal, pump will not move any fluid when I put it on the tractor. Therefore, the pump was probably not pumping hydraulic fluid before I changed the shaft seal. This is why the hydraulic fluid was not being pumped into crankcase.
With that said, this situation allowed the engine oil to be pushed into hydraulic pump through the front seal, and since engine oil is thicker than hydraulic oil, the pump was able to push it and work my hydraulics. So, basically instead of pump failure and losing hydraulics it operated on the engine oil.
So, as frustrated as I am, I will see this through, it is not in my nature to give up.
The plan of attack is as follows.
1.Rebuild the entire hydraulic pump.
2. Change 2 orings for suction mounts
3. Change 2 orings for delivery mounts.
4. Dissemble loader relief valve, clean, inspect, install new orings upon reassembly.
5. Disassemble 3pt relief valve, clean inspect, install with new oring.
6. Change hydraulic oil and filters.
7. Change breather valve on top of head cover.

After, all is torqued and reassembled I will place my hydraulic gauge on the loader port for lifting and test pressure.

I assume there is no adjustment on this relief valve like in the PTO?
I am checking this first, since the loader was blowing hoses.

Next I will check and set the PTO relief valve.

I will update as I go through this process with pictures of what I find.
I appreciate all the advice and patience you all have given.

Jason




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North Idaho Wolfman

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Both relief valves are or should be adjustable.
You might want to go one step further and pull the valve cover to clean the PVC incoming screen and ports. ;)
 

JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
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New Market, AL, USA
Thanks, I will look at it.

I wonder if the technician that told me pump should be 3500 psi, may have set one of the relief valves that high.

Also, I have the other loader control than one you posted earlier in the week. I have the one that is under return hose on flat control valve

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RCW

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I am discouraged, and at the same time thankful for the education.

Jason
Jason - this line made me respond. Unfortunately, I have nothing helpful to add.

I only want to say I have followed this from Post #1. "Losing" 6 quarts of oil in a short period caught my interest.

I have learned SO MUCH just following the problem-solving process.

Your hypothesis makes perfect sense to me, a novice, and you have some pretty sharp guys helping/advising.

Your "I will prevail" attitude is to be commended!:cool:

I'm routing for you, brother......and wish/hope you find resolution/satisfaction shortly!

Best wishes!:D
 
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rbargeron

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......my hydraulic pump appears to be bad, I'm going to have to rebuild it....... I had the pump apart and it doesn't look too complicated, but nothing beats a little experience..........
I've replaced seals in Cessna pumps, but not in this Kubota pump - but there is something that caught my eye. I'm wondering if the underlying problem here is not that the pump is bad, but that it was incorrectly assembled at some point, leading to the blown hoses and sucked-in engine oil.

Attached to post #37 was the component parts diagram for the pump - I'm attaching it here again below. On the ends of each pump gear are the Bearings G and H. These parts are the same size but are quite different in their details. They govern unit function, determining which way the unit turns, and whether it acts as a pump or a motor. As a manufacturing convenience for flexibility they may actually fit together even if not oriented right. But if assembled wrong, the pump might not work at all or could dead-head internally, blow out the seals, or possibly even self-destruct.

I haven't found videos on your exact Kubota pump design, but the general subject is covered in this instructional graphic. There's a lot of gear pump info on the web. A similar mass-produced commercial pump is shown and discussed here.

Its easy to imagine if the gear Bearings G and H and/or the keys 160 were out of position, the unit won't function right. The pump designs in the videos are different from each other and from the Kubota pump - but assembly order might be something to check into. Maybe there's a WSM that details correct orientation of the bearings.
 

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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
0
0
New Market, AL, USA
Thank you for the videos. I'm going to start the disassemble process tomorrow. I will post pictures and a few videos.


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JbirdM6800

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2008 M6800SDT Dual Traction 4WD CAB, LA1002-68C loader
May 12, 2017
40
0
0
New Market, AL, USA
Hey ya'll, just wanted to let you know what's happening. Last week the pump seals arrived for the rebuild. So on Saturday, I got to work removing the pump. However, I discovered when removing it, I made a costly mistake. When I reinstalled after changing the shaft seal, I must have run it a wee bit longer than my gut said stop. In turn, the gears in the front side of the pump broke causing the shaft shear at neck of pump where it goes into female spline on engine idler gear. I assume this is from lack of hydraulic oil due to faulty chamber seals from original overpressure. Lesson learned. If you blow any seals in a hydraulic pump rebuild entire unit, seals and orings are cheap, pumps are not.
Anyway, I have new pump arriving tomorrow, I also have all orings and seals for both relief valves. I will be looking for some advice on what to look for in the relief valves. I don't want to risk another over pressure situation with new pump. I would like to find out which one, if either, is bad before ordering. Relief valves are $300+ each.
I will post as I go over the next few days

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rbargeron

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L5450, L48, L3250, L345 never enough attachments
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........ When I reinstalled after changing the shaft seal, I must have run it a wee bit longer than my gut said stop. In turn, the gears in the front side of the pump broke causing the shaft shear at neck of pump where it goes into female spline on engine idler gear. I assume this is from lack of hydraulic oil due to faulty chamber seals from original overpressure. Lesson learned................
Good to have the update - broken pump gears are a serious event. I'm thinking there may be other gears (like the idler) that are cracked just waiting to fail next. I'd again draw attention to the last paragraph of post #48 on page 5 of this thread. The failures up to now need a thorough up-close evaluation by an experienced pump person to help stop the mounting costs. Unless you get to the bottom of everything that's happened it will be hard to trust the tractor going forward.
My 2 cents. Good luck, Dick B
 
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