G1800 hst line leak help

dylang1800

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Sep 5, 2016
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hickory nc
Ok. I posted yesterday about my g1800 not going only surging forward every few seconds. But on an incline it would pull the whole way. I tore it down and found a line that connects to the top of the hst leaking bad. Not even running and it's leaking out good. Looks as if a plate holds it down with two bolts on each side. I got some pictures gonna try and post them. Do y'all think this is yhe cause of my "slippage" and if so. How do I get that line to stop leaking. I bought fluid and filter to change it all out. THANKS
 

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dylang1800

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Sep 5, 2016
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hickory nc
UPDATE! Upon further inspection.. The two bolts next to the line does not hold it down... I have no idea wth holds it down :/. Maybe some jb weld?? Idk.. I'm tired. Worked all night then come home and tore this down lol. Please help
 

CountryBumkin

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It may be that the line is welded to the plate (the plate with the two bolts you mentioned) and maybe the line has cracked at the weld. If you could clean up the area and repost the same photo (first photo) it would be easier to see what you have.
 

dylang1800

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This is about the best I could get it atm. I can pull the back half off. But it's not like a plate that holds the line down. I'm not real sure what holds it in there.
 

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dylang1800

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This is a picture of one of the "bolts" next to th line. Doesn't look like the outside "bolt" turns. But there is one on the inside that looks like it would turn. I just haven't turned it yet because it might be some kind of an adjustment. Idk
 

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CountryBumkin

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And this is a photo from the back. YOu can see the heck head bolts I can remove to remove the back half of the pump?
Much better picture. I see that it is not using a mounting plate like I thought (I was thinking of the way an oil pickup tube is mounted to the oil pump in a car engine).

Perhaps this line in grooved and uses O-rings on it and is just pushed into housing. But if this is the way it works, it would need something to keep the line in place (like a bracket or clamp on the ridged part of the hose).
Sorry I don't have a manual so I can't provide any useful info.
 
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Tooljunkie

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That tube may just have o-rings, and other end of tube is mounted to something to hold it rigid. Any chance pipe got disturbed, like a tree branch or something that may have caused it to move or bend?
Excessive heat may have weakened o ring(s) and caused the failure.

Wolfman will be along anytime and correct us all ....
 

North Idaho Wolfman

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That pipe has a simple O-ring seal.
Remove the other end of the Pipe, Banjo fitting I do believe then pull the pipe strait up out of the HST (spray brake parts cleaner around the fitting to clean off any dirt and grime) replace the O-ring and reinstall.

EDIT:
"Wolfman will be along anytime and correct us all ...."
Agree with you all is more like it!
 
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dylang1800

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Sep 5, 2016
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hickory nc
I finally fixed it. Thank you guys. It was a no ring. The other end of the pipe was bolted to the bottom of the rearend.it had a big bolt with a nice long metal screen attached to it that went into the rearend. I took it out. Cleaned the screen, went to the hardware and bought a fatter o-ring and pressed it down in there. I put my new filter on. New fluid. Put er all back together and now it goes better than it ever did :) doesn't whine nowhere near like it did, just a small one. Only thing is now the pedal it much harder to press. And also it doesn't spring back to the "neutral" position like it should. I have to help it a little bit. But oh we'll lol I'm not complaining. I'm just so happy it works! :))
 

lugbolt

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That line (kubota calls it a "pipe") is a direct connection between the sump (trans case) and the charge pump. That's why there is a suction filter on the end of it. The charge pump is what "charges" the hydrostatic part of the transmission-i.e, the part that makes it go forwards and backwards.

There is an o-ring, you found it. It's known to fail. Some 1800's and 1900's had two o-rings on it. When it (they?) leaks, it introduces air into the hydraulic fluid. That does two things. First, it aerates the oil and two it starves the charge pump, both reducing the HST's performance. That's why it surges.

The hex head "bolt" is not a bolt-it's a plug. Under the plug is the HST high pressure relief valve and spring assembly. No sense in messing with that stuff unless it's broken.

The pedal being hard to move can be a lot of things. One potentially major issue can be the HST detent roller bearing failing. When it fails, usually the bearing has to be replaced. Just a cheap bearing but kinda tough to get to. Also, the HST swash plate's arm (on the outside of the transmission)-some of them had set screws in them that held the arm to the shaft. If the screw backs out even just a little, it makes the pedal act funny.