3-Point Hitch help please i have lost all hydraulic pressure on my MT1601D

[ch85st]

Hi
Im having major problems with the hydraulics on a MT1601D
works fine for maybe 20 min after changing all Hydraulic oil, then suddenly nothing with hydraulics work cant lift 3point hitch cant lift Front loader, I have had the Hydraulic pump repaired as i thought it might be that, and i can see i have oil coming in from the pressure pipe in to the (Buck is it called that?) I have now disassembled the whole hydraulic head under the seat and cant figure out if its the control valve thats is the problem or its something else (besides that the control valve is from a MT180D from what i van tell)
perhaps the whole hydraulic system under the seat is from a MT180 D as it dont look like a MT1601D.
does anyone have a clue to what the problem could be? im leaning to that the control valve for some reason just lets oil pass thru with out ever building up any pressure.
Grateful for any help i can get as im not usually working with hydraulics

 

[Dave M7040]

It is called a hydraulic BLOCK.

You need to provide a lot more history about your tractor and its problems.
How long have you had it,
Was the FEL on it when you got the tractor.
Have you been changing hydraulic hoses or valves, adding things like top and tilt or grapple.
Did it ever work properly.
Rarely do you make things better taking hydraulic components apart. Far more likely to make them much worse.

You need a pressure gauge to do the most basic hydraulic diagnostic tests. About $30


Post some photos of the tractor

Dave M7040

 

[ch85st]

Thank you for replying Dave
i have had the tractor 2 years and everything has been working fine up till now.
havent changed or added anything with the hydraulics on it.
Only thing that has been done is a new clutch was mounted last month. and actually the problems began after that. i noticed that The hydraulic oil had turned Black the first time it stopped working so i changed all the oil and it worked fine again for about a couple of hours and then no hydraulics again.
Changed the oil once more (yes it was black again) this time i found the filter and pulled it out (the screen is broken on it) can find a new one here so cleaned it and put it back with new oil, again worked fine for a few hours and then nothing. checked the oil black again. This time i cleaned the pump and lines with diesel (poured it in to the filler hole and run the tractor for a minute until i could see it coming back from the return on the front loader) emptied it again filled with new oil and working again for an hour or 2 . this time i pulled the Hudraulic pump and took it in to a specialize place that only works with repairing Hydraulic pumps, they took it apart and one bearing was stuck so they gave it a full overhaul and it was working fine, mounted it and still no hydraulics. so now took off the Hydraulic block to see if i by any chase could see any faults (as the pump delivers oil to the Block)
only thing i found was that the Block is from a MT180D as the control valve is not looking like the MT1601D. on the control calve the Poppet is (stuck) if its supposed to move i dont know (yet) havent stripped the Control valve yet to see if anything that is supposed to be closed is open
I will see if its possible to find one of those Pressure Gauge here in Bulgaria

 

[ch85st]

Well i got the control valve to work, even the stuck poppet and resembled the whole tractor, Still no hydraulic working.
I get oil at pressure line to Hydraulic Block, i have oil coming at return from FEL, tested connections on FEL by opening while tractor running and valve open to the cylinder, sure oil squirts out but not at a very high pressure.
So im back to the Pump i think it might pump oil but not at high pressure enough.

 

[Industrial Toys]

Be careful that you don't sustain an injury from high pressure oil which can result in amputation.

I'm thinking possible suction leak. Does the oil appear clear or foamy if run into a container?

 

[ch85st]

Be careful that you don't sustain an injury from high pressure oil which can result in amputation.

I'm thinking possible suction leak. Does the oil appear clear or foamy if run into a container?

thank you for your answer
The oil is clear no foam and yes i was careful when i was testing the the connections But as not much pressure it wasnt any big squirts just oil maybe 5-10 cm up in the air from connection.

 

[lens12]

If your loader is being supplied by the hydraulic block on the lift housing, your problem is not anything in the lift housing. I'd unhook the loader bucket line & hooking a pressure gauge on the line. See what pressure is at end of stoke.

 

[ch85st]

If your loader is being supplied by the hydraulic block on the lift housing, your problem is not anything in the lift housing. I'd unhook the loader bucket line & hooking a pressure gauge on the line. See what pressure is at end of stoke.

Thank you for the Answer
yes the FEL is supplied by the Hydraulic Block (2 hoses connected with an adapter on the side just under where the High pressure pipe comes in too the Hydraulic block)
I will try what you suggested
how ever the Hitch arms also dont work thats why i thought it might be a fault in the Hydraulic block.
I will have to get one of those Pressure gauges
Preferably before taking anything more apart (only thing i havent taken off the tractor and checked is the control valve for the FEL, starting to be a bit frustrated now

 

[lens12]

If it is plumbed correctly, which I assume it is, (unless something was changed when doing the clutch) the 3 point & loader are separate systems. The 3 point control valves have a tendency to get dirt in the relief valve & stick, but the loader should still work. The black oil is a puzzle. A common error is not hooking the hydraulics back up after working on the tractor & dead heading the pump. This blows the internal & external pump seals. Usually the hydraulic oil dumps into the motor, not vice versa. What oil are you using?

 

[Dave M7040]

Thank you for the Answer
yes the FEL is supplied by the Hydraulic Block (2 hoses connected with an adapter on the side just under where the High pressure pipe comes in too the Hydraulic block)
I will try what you suggested
how ever the Hitch arms also dont work thats why i thought it might be a fault in the Hydraulic block.
I will have to get one of those Pressure gauges
Preferably before taking anything more apart (only thing i havent taken off the tractor and checked is the control valve for the FEL, starting to be a bit frustrated now

Do NOT take the FEL valve apart. You will only make things worse.

The valve has no internal seals between the spools and the valve body. The manufacturing tolerances are so fine that without a seal oil cannot escape.

The black hydraulic oil is a clue not to be overlooked.

Is the hydraulic oil the transmission oil? If it is then there is a leaking crankcase seal from your clutch job. Perhaps the seal was put in backwards.

How many hoses on the FEL valve?

Where is the hydraulic pump mounted? When I think about you doing a clutch job, I need to know if your tractor has live pto. If the pump is not mounted on the engine, could you have not assembled the double clutch properly and now there is no power going to the hydraulic pump?

Dave M7040