kubota not runs Yeah! , but new problem

teachingscience · May 28, 2018

So last week I posted about my Kubota L185 not starting after new rings, starter and injectors.
We pull started it and it started but after about 2 minutes the hydraulic pump go so hot it started smoking. I pulled the pump off and it not starts right up. The pump was dragging it so hard it would not let it start. SOOOO now, what could cause a blockage on the high pressure side? The lift would not move at all. I did check to make sure oil was getting to the pump and that was fine so I'm assuming there must be a blockage. Have any of you seen anything like this? I was singing my praises when it started right up without the pump but this is definitely a new frustration.

Thanks to you all for your great advice.

jm. · May 28, 2018

Are you absolutely certain the pump was primed. Everything you mention points to this. You were trying to start it and it turned slow. The hydraulic pump lost prime and you pulled started it . Ran it 20 minutes dry of oil and that is why it smoked. Going back to your thinking TWO thing would have to be wrong. First flow thru the valve then the relief valve would have to have failed. If you doubt me will be easy to check just put the pump on with the DISHCARGE off. Doubt that you will see flow.

teachingscience · May 28, 2018

I did that already and yes, it had flow. Didn't start but just the starter pumped out a pretty good puddle. There is a block under the seat in the pressure line that I assume was for a loader in the tractors past. I'm starting to wonder if it is the source of the blockage.

JD Seller · May 28, 2018

Is that block under the seat a selector valve??? You may have accidently switched it over to the loader ports that more than likely are blocked.

Your tractor has an open center system on it. So the oil has to be free flowing when nothing is demanding pressure oil. Stuck pressure relief valve can do the same thing.

I would say get a hydraulic diagram showing you the pressure circuit and start looking for a restriction.

Tractorcedric · May 28, 2018

I have run into a similar problem before. What history do you have. Like, did it run before you worked on the engine or did you buy the tractor not running. Some times when a loader is removed a loop line needs to be put in place. Or the block you mentioned under the seat needs to be removed with the loader. That block would have been used to route the pressure from the pump to the loader valve.Then then a line from the loader valve would come back to the three point. If some one took the loader off and just put a plug in that block, the motor would not start right then! Don't ask me how I know!

teachingscience · May 29, 2018

I did buy not running and I'm thinking you are exactly right. When I get home today, I'm gonna check that block. I'm betting that it totally blocks the flow. What I'm wondering is if the previous owner ran it that way or if it never ran after the block was plugged.

teachingscience · May 29, 2018

Not a selector valve. It is just a block with line in and line out and two plugs on top. I ignored it because it looked old like it had been there for years. I just assumed it was the way it needed to be and didn't give it a second thought.

teachingscience · May 29, 2018

Also, it just took about 2 minutes of running for it to get that hot. After my last post last night, I took the pump off and now it starts right up like it should.

kubota not runs Yeah! , but new problem

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