1855 hydraulic in the transmission

oliver1755 · Oct 20, 2019

My 1855 went down last week. Drained the hydraulic into the rear end. I initially tried plumbing around the PTO, which I rebuilt a couple winters ago, and the drain didn't stop.

It seemed over the period of 12-18 hours that the level would go down a couple quarts.

I filled it and drove it to the shed, about 5 miles. It was below the dipstick by then.

I'm guessing the hydraulic pump? Maybe the pan? Which would you start with?

If it's the pump, I looked at the parts breakdown and it looks like you might be able to take the pump off and replace the bearing and seal without disassembling the whole pump. Is that the case? The pump otherwise works fine. Will it be obvious if it is the pump when I take it off the tractor?

Thanks

bison · Oct 20, 2019

3 possibility's .
PTO clutch piston seals leaking.
Hydr pump seal leaking.
Hole in the hydraulic tank floor plate.

Take your pick.

WadeBH · Oct 20, 2019

I am having a similar problem with a 1755. Which of the three sources provided is most likely the cause? And, what work is involved with repairing each of these?

bison · Oct 20, 2019

(quoted from post at 13:48:20 10/20/19) I am having a similar problem with a 1755. Which of the three sources provided is most likely the cause? And, what work is involved with repairing each of these?

The Pump runs all the time and is the most likely to have a defective seal.The pump has to be removed and disassembled to get to the seal.
The PTO if it is frequently used with engage and disengage it is the next one to have failed seals me thinks. You'll have to remove and disassemble the whole PTO unit.
The hydraulic tank pan can have a hole rusted in or one the bull gears could've worn a hole in it if the axle bearing got sloppy.The bull gears clear the pan by only a smidgen.You have to remove the top of the transmission/rear end.

bison · Oct 20, 2019

The PTO system can be tested by removing the pressure line from the PTO valve and applying air pressure to the port with the spool in engaged position. It should hold pressure in both engaged PTO and brake on position ,.if not then you got a leaking piston seal in either the brake or run position.

WadeBH · Oct 20, 2019

Bison, thank you for the follow-up. I will keep this thread for reference when I get into that project this winter.

J. Schwiebert · Oct 21, 2019

Have you tried to block the lines to the PTO valve? Around here PTO's are not used much so we would have the farmers plug those lines till they could spare the tractor. There were design changes in those seals too. On the pump I would also check the flow from the case drain. It may save you taking the pump off twice. Questions, e-mail me. J.

oliver1755 · Oct 21, 2019

Will the pump seal leak when it sits overnight?

I plumbed around the PTO so I'm confident that isn't the problem. Obviously I'm at the pump or the pan. If the leak only goes down some sitting without running then "stops", I'd think that's the pump, but I
was not sure if it would leak out of the pump some without running.

Thanks

1855 hydraulic in the transmission

oliver1755

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bison

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WadeBH

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bison

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bison

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WadeBH

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J. Schwiebert

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oliver1755

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