M8560 lost hydraulics?

[jca57jd]

Good evening. I have a m8560 12 speed with roughly 320 hours on it. Just did a full service on it about 20 hours ago using all Kubota genuine filters and fluid; oil change, all filters, and top off hydraulic fluid. I bought this tractor with about 200 hours on it and it has always had a 15’ batwing hooked to it since I bought it. Last week I mowed a 10 acre field and parked it beside my barn. Had no problems what so ever with the tractor or hydraulics when I was mowing. Cranked it up yesterday and the batwing ever so slightly raised and then i suddenly lost all hydraulics to the remotes, and loader? Power steering and hydro clutch still work fine, hydraulic fluid level is good. I visited 2 local dealers and they were zero help leading me to a good starting point on solving this problem, just the simple “gotta bring it to me for me to help”. I’ve researched a good bit on here looking for this problem on similar models and can’t seem to find where anyone has had this problem. Any advice would be greatly appreciated!!

 

[Harry in Ky]

Assuming the three point is dead as well? As I see it, there is a two stack pump on the right side of the tractor driven off gears in the transmission. One single inlet and two outlets. Since one section seems to be working that mostly rules out a suction problem. Typically with that sort of problem I would loosen the three bolts on the pump outlet pipe a few turns, set three point controls to full down, then start the engine. let it run at just above idle for a few seconds and shut it off. Then look under there to see if the pump moved any oil. Sometimes that's all it takes, and things go back to work. Not always, but it's simple, cheap and only takes a couple minutes.

 

[jca57jd]

Harry, Many thanks for the reply sir!! I will try that asap!! On a side note this pipe in this picture gets hot (9?*) real fast (tractor running for 2 minutes or less). Is that a sign of anything? Thank you sir!!

 

[Harry in Ky]

It tells me you have a valve stuck somewhere, and oil flow is going nowhere. Just building pressure in the system (maybe going over relief) causing the heat, with oil flow not getting to the loader valve, remotes and lift system. Seems odd because the loader valve is usually first in line for oil from the pump so at least that should work. Check the remote levers to make sure one of them isn't stuck on or something.

 

[oldnslo]

Jc
a line getting hot would indicate flow escaping under pressure like something could-be restricting flow causing it to go over a relief valve. On some models if the 3 point lever gets pulled back can block flow causing this but not sure if this would cause all loader functions to stop.

 

[Tx Jim]

One possibility is feedback rod for 3pt isn't adjusted exactly correct. If 3pt is fully raised move control lever forward about 1/2''.

 

[jca57jd]

After taking some covers off this morning, it looks like the pump has 2 outs; 1 going to power steering, and the other feeding the loader and remotes. The line feeding to the loader and remotes goes into the loader 3rd function auxiliary block first, then comes from the third function block to feed the 2 valve spools for the loader, and finally a line comes from the top of the loader valves and feeds the 2 rear remotes. It looks like my problem must be in the 3rd function control box (the only hydraulic function that has electronic over hydraulic controls). Everything runs through it first and it also has the return line that is getting hot fast hooked to it. No I gotta figure out what is wrong with it.

 

[5030]

How both my M9's are set up. 2 section pump with a common feed. One for the steering and one for everything else. One thing you don't want to do is destroy the pump. Very expensive to replace and basically not rebuildabe.

 

[Harry in Ky]

After taking some covers off this morning, it looks like the pump has 2 outs; 1 going to power steering, and the other feeding the loader and remotes. The line feeding to the loader and remotes goes into the loader 3rd function auxiliary block first, then comes from the third function block to feed the 2 valve spools for the loader, and finally a line comes from the top of the loader valves and feeds the 2 rear remotes. It looks like my problem must be in the 3rd function control box (the only hydraulic function that has electronic over hydraulic controls). Everything runs through it first and it also has the return line that is getting hot fast hooked to it. No I gotta figure out what is wrong with it.

So what is this "third function block"? Is that something added on? Parts list shows nothing like that. From your last post I think you found your problem.

 

[jca57jd]

I worked on it for about 6 hours today. The third function kit is an oem kit but makes all the hydraulics run through the third function block which has a hydraulic valve solenoid ontop and has a the hydraulic supply for the loader coming out of it. For whatever reason the hydraulic valve solenoid prevented the fluid from passing through with a blockage. I started off by bypassing the third function and got everything else running. Then I started diagnosing the third function part. I found one of the 2 relays was bad and changed it but I felt pretty sure the hydraulic solenoid valve was hung in one direction (only thing that made any since for my mild mechanic knowledge). Tore into it by removing the solenoid valve and one side had the coil stuck and seized up with the cap. Cleaned everything good and put it back in and hooked the hoses back up going through the third function and got the loader and remotes working okay at the moment. When I run the third function I can hear and feel it load in one direction but not the other so I guess one of the coils is bad. I don’t really ever use the third function (auxiliary hydraulics) on the front but I’m trying to keep everything working properly. Thank all of you that helped me figure out a good starting point!! Harry your knowledge and help gave me the confidence to tear into today!! Thanks again!!