Is 3 Pt Hitch Leakdown Normal?

[J_J]

It appears you have a leak as others have said. Some 3pt cylinders are not as good as others, and as they wear, the situation gets worse. Most of them will leak soon or later. New seals/o-rings maybe. Or, trash in the circuit causing leak down.

 

[CompactTractorFan]

I noticed after I turn off my tractor and it sits a while everything seems to "leakdown" (Mower, Backhoe...etc...). Also the mower seems to drop some while I'm driving around especially in rough terrain. Is that normal? This on a BX25. Oh, and I'm not trying to threadjack...

 

[jinman]

To help isolate the problem, I think you can do a test. You should have a needle valve that adjusts how fast the 3PH normally drops. Raise the 3PH and shut that needle valve completely off. Then, shut off the tractor and watch the 3PH. If it drops, the problem is likely to be lift cylinder seals. If it does not drop, then the problem might be in the 3PH control valve.

 

[mmurphy]

Is it possible to look in casing with tractor off to see 3ph cylinder? If you can, possible to see dripping coming from end of cylinder.

 

[dfkrug]

No one has mentioned the 3-pt load check valve yet. On my Deeres,
they are on the top of the 3-pt cylinder housing and have large hex
heads. When removed, there is a spring and ball in there. It is
separate from the relief valve, which can look similar.

I do not know your machine, but all my CUTs have had load check
valves. The ball could be corroded or dirty.

 

[genusCastor]

To help isolate the problem, I think you can do a test. You should have a needle valve that adjusts how fast the 3PH normally drops. Raise the 3PH and shut that needle valve completely off. Then, shut off the tractor and watch the 3PH. If it drops, the problem is likely to be lift cylinder seals. If it does not drop, then the problem might be in the 3PH control valve.

I finally got a chance to test this, and it does drop with the valve shut off. So that seems to indicate a cylinder seal problem(?) Is there something else to test to isolate the problem?

Thanks, everyone.

- djb

 

[jinman]

I finally got a chance to test this, and it does drop with the valve shut off. So that seems to indicate a cylinder seal problem(?) Is there something else to test to isolate the problem?

Thanks, everyone.

- djb

It is possible that your Mahindra is mechanized much like my NH, a Kubota, or a Deere. Without seeing a diagram, it's really speculation, but experience would say that it is probably similar to all these systems. I'd surely post in the Mahindra forum so you can get an accurate comparison from other Mahindra owners. They can verify whether your dealer is giving you good info or not. If this were normal, I'd expect to hear a lot about it in the Mahindra forums.

That said, Dave raises a good suggestion about the load check valve. If you can gain access to the valve and check it for cleanliness, it sure wouldn't hurt anything to do that check. On my New Holland, the needle valve is in parallel with a ball check valve and high pressure relief valve. If the ball valve is leaking it would allow the lift to drop, but you have to consider that this ball valve gets "washed" everytime you lift your 3PH. Surely, trash would have a hard time building up there in a normally clean system that showed no signs of contaminated fluid. I think it is far more likely that you have a slow leak in your lift cylinder seal.

 

[genusCastor]

...trash would have a hard time building up there in a normally clean system...

Trash in the system has been mentioned before and I'm curious, how could anything get in? I'm guessing it could only be when someone has the system open and lets dirt, etc., get in(?)

I'll post a question to the Mahindra folks. :thumbsup:

- djb

 

[dfkrug]

If the ball valve is leaking it would allow the lift to drop, but you have to consider that this ball valve gets "washed" everytime you lift your 3PH. Surely, trash would have a hard time building up there in a normally clean system that showed no signs of contaminated fluid. I think it is far more likely that you have a slow leak in your lift cylinder seal.

That's a good point.

Also, the cylinder is single-acting, so a leaky piston seal would indeed
cause the three point to sink on its own (vs. for a DA cyl).

As for a non-functioning load-check RV, I imagine that the spring could
break, or a long time of non-use could allow corrosion or sediment buildup. I
once found corrosion in an Iseki hyd PTO diverter valve, which was not
used for a very long time. I know non-use does not apply to the OP's
case.