3-Point Hitch Hydraulic lifts slowly drop over night

[Jerry/MT]

This morning, I lifted the 3PH all the way and turned the drop speed needle, photo attached, valve clockwise until it stopped turning, closing it completely. But it still dropped half way after 5hrs. I still don't see any leaks anywhere, photos. If the lift cylinder is leaking would I see the leak?
Oh, by the way where is the lift cylinder? Sorry for the inexperience....

Don't know about your tractor but the lift cylinder is usually under the lift cover which is below the seat. You can't see it leaking unless you look into the hydraulic compartment. Half way in 5 hrs ain't much of a leak. How many hours on the tractor?

 

[Soundguy]

i agree... some drop in 5 hours is a real non issue.

to the OP.. the lift cyl is usually coupled to the rocker shaft which is connected to the upper lift arms.., all under the seat.

ps.. leak would be internal..

soundguy

 

[jinman]

I think the most likely culprit amongst the others is leaky piston seal that will be your cheapest and easiest fix considering the design.

I agree that this sounds like the main piston seal is leaky. With enough use, it might even get better. JC, I don't think it is likely the ball-check valve you discussed because that ball check gets "washed" each time the lift is raised. It could be, but my estimation of it's possibility is very slim.

As others have pointed out, in operation, that amount of leakage is not going to mean much. With use, it could get worse or it could get better. If the tractor was under warranty, I'd want it fixed; however, with a used tractor, I'd just use it that way until it becomes a problem. Of course, if it drops that much with no load, it might come down much quicker with a boxblade on the 3PH or other heavy implement like a rotary cutter. I'd sure check it with my heaviest implement to make sure the lift is not dropping and "hicupping" at a high rate of speed.

 

[JC-jetro]

I agree that this sounds like the main piston seal is leaky. With enough use, it might even get better. JC, I don't think it is likely the ball-check valve you discussed because that ball check gets "washed" each time the lift is raised. It could be, but my estimation of it's possibility is very slim.

As others have pointed out, in operation, that amount of leakage is not going to mean much. With use, it could get worse or it could get better. If the tractor was under warranty, I'd want it fixed; however, with a used tractor, I'd just use it that way until it becomes a problem. Of course, if it drops that much with no load, it might come down much quicker with a boxblade on the 3PH or other heavy implement like a rotary cutter. I'd sure check it with my heaviest implement to make sure the lift is not dropping and "hicupping" at a high rate of speed.

I agree Jim that the ball check is unlikely to be the culprit. I think the point I was trying to make is, I too though closing the rate of return will keep the implement in the air if the piston seal was okay, till I saw the geometry of flow and potential path back thru the big ball check.

With the rate of drop knob fully closed you can still raise the implement some ( up to pressure relief) but can't lower it. That's what I got from the first diagram I showed. It also says that diagram is common amongst all models.

JC,

ps. I don't think the OP has a major issue, and checking the piston seal is a 1 hr job tops and it is very inexpensive. I don't know if there is any deco rational sheet metal needing to be taken off to have access to cylinder head. On my 1700 it is in plane view, nothing in front it and takes a few (6) bolts to take it off.

 

[RobertN]

Just curious, why would you leave the 3pt "up"?

I've always been in the habit of parking with the loader and the 3pt down. Partly safety; before I had the tractor shed, the tractor was next to the house. didn't want to risk the kids getting on it and having a loader or boxscaper wind up on thier foot. And, it takes pressure off all the rams and seals.

 

[ArtMech]

Then a conclusion we are comming to is, that there's nothing in common with a filter change.

 

[JC-jetro]

Then a conclusion we are comming to is, that there's nothing in common with a filter change.

None, at least with TC hyd lift design. I too never let any implement hanging from the 3 point when the tractor is in storage. There is nothing to gain by it other than occasional mishap that might prove to be quite dangerous. I lower stuff on pieces of wood planksand totally dissipate pressure from my hyd system.

JC,


ps. Stored energy need to be respected in any forms.

 

[Eastbx]

So this all sounds a bit complicated but the main idea is watch for drop during operation. If drop becomes issue I should replace piston seal, right? JC - I opened that PDF and it has many parts, this may sound stupid, but which seal/gasket are we talking about. I really don't want to take that cylinder apart and still not know what to replace.
It is painfully obvious this is my first tractor, I obtained used with 685hrs.
By the way I normally leave the 3PH down, I left it up when I changed the filter.
Although this issue is still pending I want to Thank you Gentlemen for the help.
Eastbx

p.s. when I put something heavy on the 3PH, it shouldn't drop at all with or w/o the tractor running, right?

 

[RobertN]

Sound just like me when I joined back in '98. Although the sig line says 2000, there was a previous iteration of this website around for a couple years previously.

Amazing what I have learned around here over the years. And still learn...

It is painfully obvious this is my first tractor, I obtained used with 685hrs.

 

[ArtMech]

So this all sounds a bit complicated but the main idea is watch for drop during operation. If drop becomes issue I should replace piston seal, right?

Eastbx, don't give way to despair. Look, I do believe someone from TBN who's more experienced in the design of Your machine will really help You if even the replacement of piston seal will be needed. I could and I should help the owner of a tractor, but the same like mine.
So if You'll really could not operate Your tractor, all You have to do I guess is to open another thread on the new issue.