Twice I've had hydraulic oil blow out from under the 3 point piston cap. Seems to happen when I have my 3 point in the UP position while using the front end loader. I've recently replaced the Orings inside the 3 point control valve but did not touch the release valve or poppets. What could be causing this? Any help would be appreciated.
Kubota B7200D 3 point hydraulic issue
- Thread starter Canuckhunter
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TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
On that tractor the 3pt can be locked in the full up position which deadheads the pump.
The loader should not be feeding the 3pt unkess both spools are in neutral. What model loader and what valve is on it?
Dan
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I mounted a John Deer loader with a Hydro Works two spool joystick FEL. Worked great for 3 years but I developed a leak from my 3 point lever. After changing the O Rings, I started having this problem.
I was suspecting what you are saying, that it was dead heading on top of the piston.
Would a stop lever on the line feeding the 3 point work when the loader is in use?
Thank you for your input.
I was suspecting what you are saying, that it was dead heading on top of the piston.
Would a stop lever on the line feeding the 3 point work when the loader is in use?
Thank you for your input.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
I havve had no problem with mine but it has a Kubota loader on it. Does your loader have separate power beyond and tank return lines?
Dan
Russell King
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L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
The leaking around the shift lever indicates that your transmission vent is clogged, Have you checked it?
probably a tube under the seat area on top of the case.
TheOldHokie
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The contril lever is fixed. His current problem is the cylinder head on the 3pt lift cylinder.
Dan
It's not leaking there. It blows out from under the piston cap causing me to loose most of my fluid. Makes one hell of a mess.
Yes I have return lines. Loader ran great for 3 years. Everything started after I replaced the o rings in the 3 point assembly valve.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
I am having difficulty connecting those o-rings to the cylinder cover. Maybe the timing is just a coincidence. Sounds like you may be over pressuring the lift cylinder and I am trying to figure out how that could happen. Do you own a hydraulic pressure gauge?
Dan
Russell King
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My thinking is that a clogged vent wants to push oil out of the transmission case WHEREVER IT CAN. I understand that you fixed the leak on the shift lever by putting new o-rings. BUT now you have another leak from the same possibility over pressurized case.
It is simple to check but I really don’t know if it can cause the leak you currently have.
ignore the suggestion or use it to eliminate the possibility.
I plan on getting a pressure gauge. I was thinking maybe one of the relief valves in the 3 point might be messed up. I did notice the engine speed change when the 3 point is fully raised. Sounds like the pump is pressurizing and causing the engine to reduce speed??
TheOldHokie
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You are cinfirming my suspicions. Sounds lke you are placing the three point lever in the gated offset at the top of the guide slot.
That position locks out the feedback mechanism and prevents the pump from shutting off when the lift hits top of travel. That deadheads the pump against the cylinder and should only be used if you are using the optional rear remote outlet.
Dan
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That makes sense but I'm not sure why I didn't have issues before. In the 3 point assembly, there's 2 nuts on shaft #7 as illustrated and I did take that apart but didn't know how to properly adjust it. Maybe that's part of my problem? I don't see anything in the shop manual? Thanks for your help.
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North Idaho Wolfman
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Could be a mal adjusted feedback linkage, keeping the three point engaged when its all the way up.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
The B7200 3pt control has a special position that does exactly that.
It is used in conjunction with the optional reat remote outlet. When the lever is moved into the offset notch at the top of the guide plate (area highlighted in blue below) the feedback linkage is disabled and the spool in the position control valve is locked in the raise position. If the remote outlet is not in use the pump will be deadheaded against the 3pt piston and the hydraulic pressure spikes to max system pressure and stays there. Now on my B7200 that does not cause a blowout of the oring seal on the lift cylinder cover but it will tax the pump.
The reason I asked about the plumbing on his loader valve is I was considering the possibility of having a loader cylinder in series with the 3pt cylinder. Its possible in a series connection scenario to create rod end pressure on a loader cylinder that exceeds system relief pressure and overloads the dead ended 3pt cylinder. That would explain the OPs perceived connection between loader operation and blowout.
Dan
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