Three point hitch slow leak down and hiccups when in use

[Stewartkyle44]

Hello all. I am looking for some answers to where my leak may be coming from. My three point hitch leaks down when not in operation and when it’s in operation it hiccups. The only noticeable external leak I can see is where the PTO shifter shaft from 540/1000 goes into the rear pto housing but it is a small minimal leak and I didn’t think it would be loosing that much pressure to cause the full leak down of three point hitch when tractor is off in about 10 minutes. Was curious if I should start there or is it most likely an internal leak up at the rocker arm shaft. Any help would be appreciated.

 

[TractorTech]

Welcome to TBN. The internal 3pt piston seal is leaking by. Most likely and hopefully, it will just require replacing the oring and backup ring on the piston.
The external leak doesn't have any connection to the 3pt.

 

[Stewartkyle44]

Thank you for the quick response. I attached another picture of a parts diagram to just confirm you are talking about part #8 and #20 correct? Where would the oil be going to if it was seeping past the piston when lifted, just back into the transmission housing?

 

[TractorTech]

Yes, those are the parts. Only other thing that might be wrong, but usually not on a low houred machine, is that the cylinder has some scoring.
The oil leaks by back to the sump/transmission

 

[Stewartkyle44]

The tractor has 1900 hours on so hopefully I don’t have to replace the piston but if I do it’s not too expensive at around a 100 dollars. My concern is I have a DK55c (cab model) and if it really requires removing the cab to get to the upper housing off and access to the piston and seals?

 

[TractorTech]

The piston isn't the problem, even scored, it doesn't affect the sealing. The cylinder #1 would be scored. The scoring, if minor, can be taken out with a hone.

I believe, but can't really tell, that the cylinder can be accessed inside the cab by taking an access plate out or the seat assembly out.

 

[Stewartkyle44]

Okay thank you. One last questions, any tips/tricks or special tools to change the o ring or backup ring?

 

[rScotty]

Okay thank you. One last questions, any tips/tricks or special tools to change the o ring or backup ring?

The other place the 3pt hitch arms can leak down is via the needle valve that traditionally is under the front of the tractor seat. That needle valve regulates the speed that the arms can fall or if turned all the way in it lhydrauically ocks the 3pt arms in whatever position they are in - if there is no leakage in the piston O ring itself.
So you can use that valve to see if you need to replace the O rings in the piston. That needle valve also has tiny O rings, and it dumps the fluid into the same internal sump as the rest of te 3pt system.
rScotty

 

[TractorTech]

Once you have the piston out, just a pick or small blade flat screw driver to remove. Since they are probably the cause, a knife to cut them out and a very careful stretching of the new rings onto the piston.

 

[Stewartkyle44]

Awesome thank you very much for the support and quick responses!