Hydraulic problem.. I'm stumped

   / Hydraulic problem.. I'm stumped
  • Thread Starter
#11  
Old fellow
How many hoses are connected to the loader valve? 6 or 7

From your description there should be 7.
Pressure in
Power beyond
Tank
2 for loader
2 for bucket

is this correct?

When you shift one of spools in the loader valve does oil still come out the power beyond port on that valve?
7 hoses.
I didnt try that test yet, but I did notice that that fluid did start to come out of the tank hose (low pressure return to the transmission) when i moved the joystick to any position, which it is supposed to do according to the manuf. I also then tried removing each of the 4 channel fitting on the lines to the loader cylinders, and when I move the joystick to that respective channel, a little bit of fluid comes out, but only a low slow, flow (regardless of engine rpm) clearly not enough to actually operate the loader.
So now I have the feeling that feeling that there's actually insufficient pressure/flow reaching the valve from the tractor. Fluid does come out of the main supply hose for the controller, but maybe its not at enough pressure to actually move the loader. Going to check the supply line for power beyond and hydraulic pump supply side hoses for problems like Carey suggested, havent had time to get to that yet
 
   / Hydraulic problem.. I'm stumped #13  
When moving the joystick the only flow that should come out the tank line is return oil from the cylinders moving or system relief opening. Other possible flow path is if the power beyond plug is leaking but that usually prevents the 3 point from working properly.
 
   / Hydraulic problem.. I'm stumped #14  
There was a valve under the seat of my tractor that stopped the front loaders from working.
 
   / Hydraulic problem.. I'm stumped
  • Thread Starter
#15  
7 hoses.
I didnt try that test yet, but I did notice that that fluid did start to come out of the tank hose (low pressure return to the transmission) when i moved the joystick to any position, which it is supposed to do according to the manuf. I also then tried removing each of the 4 channel fitting on the lines to the loader cylinders, and when I move the joystick to that respective channel, a little bit of fluid comes out, but only a low slow, flow (regardless of engine rpm) clearly not enough to actually operate the loader.
So now I have the feeling that feeling that there's actually insufficient pressure/flow reaching the valve from the tractor. Fluid does come out of the main supply hose for the controller, but maybe its not at enough pressure to actually move the loader. Going to check the supply line for power beyond and hydraulic pump supply side hoses for problems like Carey suggested, havent had time to get to that yet

After finally getting time to revisit this problem, I did as Harry suggested and got a pressure gauge, and installed it on an extra input port of the loader joystick controller (as instructed by Eric from Brand Hydraulics, the maker of the controller). Eric told me that if my hydraulic system was "closed center", I would see pressure on the gauge as soon as I started the tractor, and if it was an "open center" system, I would see pressure register on the gauge when I moved the joystick to any (non-neutral) position.
The result was that no pressure showed up either way.

However, when I raised the 3pt hitch control, the pressure on the gauge (still mounted on the joystick control valve) shot up to 2000psi and stayed there as the Yanmar relief valve (the one on the tractor itself) squealed (as always happens when the 3pt reaches top of its travel and lever is still held in the 'raise' position).

Given that the joystick controller was now getting pressure in this condition, I tried simultaneously operating the loader joystick, and then the loader moved. But as soon as I moved the 3pt lever back to neutral, the pressure to the joystick controller went to zero and of course the loader no longer operated.

So I at least confirmed that the hydraulic pump is working fine, but I'm still stumped by how the flow to the loader valve has changed like this (now requiring the 3pt to be in the raise position, where it never had to be before). I've been trying to locate a schematic map of the hydraulic system on this tractor but haven't had much luck so far. Also tried calling Hoye tractor, but Aaron is no longer there (sold the business) and the people there now didn't have any insight into my problem. They only suggested me to check the hydraulic lockout valves (which are both open), and also mentioned that "perhaps it was a line clogged somewhere". But there's only one line supplying the loader valve, which is connected to the divider block on the right rear fender. Previously there was always pressure flowing in this line whenever the engine was running, but now it apparently only reaches this line when the 3pt lever is raised.
Yanmar 186d hydraulic circuit map.jpg

I did manage to find this map, though it's not the most user-friendly. The path looks like the divider block circled in red (where the loader input hose is connected) is a straight shot just directly downstream of the hydraulic pump (D), while the "control valve spool" ("M", that I guess operates the hydraulic lift cylinder) is all downstream of the output block, and in fact appears to actually get all its fluid after first going through that block. So it doesn't seem to make sense that the loader valve can only work/get pressure when this (downstream) control valve spool is opened. Unless there was some kind of backflow going on.. but the diagram doesn't seem to show this would be possible..
 
   / Hydraulic problem.. I'm stumped #16  
After finally getting time to revisit this problem, I did as Harry suggested and got a pressure gauge, and installed it on an extra input port of the loader joystick controller (as instructed by Eric from Brand Hydraulics, the maker of the controller). Eric told me that if my hydraulic system was "closed center", I would see pressure on the gauge as soon as I started the tractor, and if it was an "open center" system, I would see pressure register on the gauge when I moved the joystick to any (non-neutral) position.
The result was that no pressure showed up either way.

However, when I raised the 3pt hitch control, the pressure on the gauge (still mounted on the joystick control valve) shot up to 2000psi and stayed there as the Yanmar relief valve (the one on the tractor itself) squealed (as always happens when the 3pt reaches top of its travel and lever is still held in the 'raise' position).

Given that the joystick controller was now getting pressure in this condition, I tried simultaneously operating the loader joystick, and then the loader moved. But as soon as I moved the 3pt lever back to neutral, the pressure to the joystick controller went to zero and of course the loader no longer operated.

So I at least confirmed that the hydraulic pump is working fine, but I'm still stumped by how the flow to the loader valve has changed like this (now requiring the 3pt to be in the raise position, where it never had to be before). I've been trying to locate a schematic map of the hydraulic system on this tractor but haven't had much luck so far. Also tried calling Hoye tractor, but Aaron is no longer there (sold the business) and the people there now didn't have any insight into my problem. They only suggested me to check the hydraulic lockout valves (which are both open), and also mentioned that "perhaps it was a line clogged somewhere". But there's only one line supplying the loader valve, which is connected to the divider block on the right rear fender. Previously there was always pressure flowing in this line whenever the engine was running, but now it apparently only reaches this line when the 3pt lever is raised.View attachment 850605
I did manage to find this map, though it's not the most user-friendly. The path looks like the divider block circled in red (where the loader input hose is connected) is a straight shot just directly downstream of the hydraulic pump (D), while the "control valve spool" ("M", that I guess operates the hydraulic lift cylinder) is all downstream of the output block, and in fact appears to actually get all its fluid after first going through that block. So it doesn't seem to make sense that the loader valve can only work/get pressure when this (downstream) control valve spool is opened. Unless there was some kind of backflow going on.. but the diagram doesn't seem to show this would be possible..
The hydraulic flow "dividing" actually happens inside the 3-pt control block. So your not having power until you move the 3-pt hitch lever is consistent with your experience and the diagram.

It looks to me as if there is some issue with the 3-pt hitch valve or lever. Clog, lever misalignment or something wrong with valve mechanism itself.

The good news is you now know where to look in more detail.

All the best,

Peter
 
   / Hydraulic problem.. I'm stumped #17  
"You know where to look?" Actually no you don't, because if you did you wouldn't be here asking about it. What you need to do is take (and post) some photos of your loader valve from different angles so we can see what you see. Show us where the oil flow comes from, where it enters the loader valve, where it exits, where it goes back into the lift system, etc. Take as many as you like, there's always room for photos.
 
   / Hydraulic problem.. I'm stumped
  • Thread Starter
#18  
Thanks guys for the input.

Here are some photos
The blue and green taped hoses are on the output side of the hydraulic joystick valve; The blue one goes to the transmission/sump, and green goes to return/input on the divider block
The hose without tape on port at the bottom of the joystick is the input, and comes there from the output port of the divider block.
One of the photos shows the hydraulic gauge attached to the second input port at the bottom of the joystick valve, and photo was taken when it was showing 2000psi due to the 3pt lever being pulled.
One more bit of info is another page from one of the manuals: a piece of info circled in red describes how you install an interior plug *inside* the divider block to block passage to the hydraulic control valve (3pt) when installing a flow meter (and also when installing a loader). This sounds relevant to the issue of interplay between the joystick controller and the 3pt controller..
 

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   / Hydraulic problem.. I'm stumped #19  
I am old and slow and don't have a real good understanding of this whole thread. However, if this system worked correctly for 6 years and nothing has been changed then something must have went bad. However again, it would not be hard to check the headless plug that is spoken about. I guess it is possible that plug could have backed out. It is necessary for that plug to be installed in order for your setup to perform correctly.
 
   / Hydraulic problem.. I'm stumped #20  
My take as well. I finally got the photos large enough to read the print and concluded the internal plug inside port A must be part (or most) of the problem. That would be the next place I would look.
 
 
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