Hydraulic problem.. I'm stumped

[old grayfellow]

Epilogue:

I had also been having another annoying issue for months; my attachments on the 3pt hitch were tending to sink down while in use. I'd presumed that it must have been a bad o-ring on the 3pt cylinder (which to my knowledge hadn't ever been replaced since new). So I had bought an o-ring and seals needed to replace that, wasn't looking forward to that job.
But since I re-tightened that allen plug, the sinking problem no longer happens! Makes sense, I guess the fluid must have been leaking past that plug while it was loose but still partly in place, a leak that would cause the 3pt cylinder to sink over course of a few minutes.

So for anybody who has one of these plugs installed: if your 3pt is sinking, check the plug tightness!

 

[grumbolt]

i hate to necro a post, but does anyone have knowledge of if a plug should be used in a 1602 with the loader attachment installed? i have just acquired a 1602, the hydraulics for the loader only work with the valve under the seat fully closed, and the arms lever all the way up. the only way the lift arms work for the back of the tractor work is if you open the valve under the seat and close the supply valve to the loader.

the valve under the seat seems to lock the arms in place so i can set them to a spot where i need them, then open the supply valve to the loader attachment, close the valve under the seat, and then use the loader. i have read that closing the supply to the loader and the valve under the seat at the same time is bad on the pump, so i havent tried that. i want to be able to let my 16 year old learn to use the tractor and implements but with the valves being critical like i suspect they are, i am leery of it. i would love for the rear lift arms and the loader to both work at the same time independently of each other.

any help would be greatly appreciated.

i am trying to translate the parts catalog into english but dont see any reference to that plug. honestly the 1602 has proved difficult to find documentation on. any links to info would be greatly appreciated as well.

thanks, Grum

 

[winston1]

I see no parts manual for a 1602 but can only assume is is like a n 1802 or 2002 which have a little different setup then the 186. The headless plug will go in a different location.

 

[grumbolt]

I see no parts manual for a 1602 but can only assume is is like a n 1802 or 2002 which have a little different setup then the 186. The headless plug will go in a different location.

thank you very much!

it looks like my setup may be installed wrong, my valve looks like the one in the above attachment, but i only have 2 hydraulic lines going to my loader implement controls.

one pressure port one, and one going back to the side of the case returning the fluid to tank.

is the rest of the book you posted from available as a pdf by chance?

 

[grumbolt]

i went and took some pics, and it looks like part of my tractor is a 1502..

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[grumbolt]

it also looks like the loader attachment only has 2 ports.. a pressure and return.

 

[winston1]

i went and took some pics, and it looks like part of my tractor is a 1502.. View attachment 4439536View attachment 4439537View attachment 4439685

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Yours is not quite the same as the1802. I am not aware of a diagram that matches your pictures. I would suggest you do away with your present setup and do it this way.

Yanmar Tractor Loader Install Instructions

Installing a loader on your Yanmar tractor.

web.archive.org

Hydraulic Compression Fitting (add a loader, log splitter, etc)

Yanmar Hydraulic Compression Fitting Sold Individually. You will typically need to per tractor. Made In Germany. Very nice Quality. 3/8" NPT Male Thread Installation Tips:Measure your steel pressure line to be sure that it is roughly 0.47" diameter. There are some Yanmar models that have a...

brandmparts.com

 

[grumbolt]

Yours is not quite the same as the1802. I am not aware of a diagram that matches your pictures. I would suggest you do away with your present setup and do it this way.

Yanmar Tractor Loader Install Instructions

Installing a loader on your Yanmar tractor.

web.archive.org

Hydraulic Compression Fitting (add a loader, log splitter, etc)

Yanmar Hydraulic Compression Fitting Sold Individually. You will typically need to per tractor. Made In Germany. Very nice Quality. 3/8" NPT Male Thread Installation Tips:Measure your steel pressure line to be sure that it is roughly 0.47" diameter. There are some Yanmar models that have a...

brandmparts.com

that is a great option! thanks very much! should i worry about a pressure relief valve?

 

[winston1]

that is a great option! thanks very much! should i worry about a pressure relief valve?

You have a relief valve built in your loader valve as well as one in the three point. Again, I can't be sure of your system, but, I can tell you the stop valves on the different models of these old Yanmars operate differently. I believe the stop valve on your model is also used to control down speed on the 3 point lift according to the weight you have on it. It can also be used to lock the 3 point in the up position as you have alluded to earlier. You will get squealing if you closed that valve completely and then try to raise the 3 point. Doing that on the models with the control valve on top can cause pump damage. or total destruction. Not good with words, hope this all makes some sense.

 

[grumbolt]

You have a relief valve built in your loader valve as well as one in the three point. Again, I can't be sure of your system, but, I can tell you the stop valves on the different models of these old Yanmars operate differently. I believe the stop valve on your model is also used to control down speed on the 3 point lift according to the weight you have on it. It can also be used to lock the 3 point in the up position as you have alluded to earlier. You will get squealing if you closed that valve completely and then try to raise the 3 point. Doing that on the models with the control valve on top can cause pump damage. or total destruction. Not good with words, hope this all makes some sense.

looking at my loader spool valves i dont see a relief valve, so i plan on changing the sanyo 2 gang valve out with something like this

amazon spool valve link with built in adjustable relief valve. this way i can have a spare port used for dump trailer hydraulics etc..

in recent past, i have added a metric washer to my relief valve spring in the 3 point to increase the pressure available to the loader being that it would bypass when trying to pick up a full bucket of dirt (the bucket is only 27 inches wide) when i replace the spool valves on the loader and change the plumbing as you suggested, i might be removing the washer in the relief valve. honestly, when it was bypassing, it wasnt making the typical noise you would expect from a hydraulic bypass valve.

i found this kit for the pump line, Yanmar Tractor Hydraulic Pipe Replacement Kit

i have the banjo fittings, and am probably gonna make the adapter at work and save a few dollars lol...

it is a pretty simple piece, 2 o-ring lands, a center tapped hole, and 2 through holes lol.. i will probably make mine with recessed socket head allen bolts so that positioning the #8 swivel fitting is easier.

any input you may have will be much appreciated. you have been a massive help in figuring out this little tractor. i grew up on a tiny farm, but we never had tractors, we either used a mule or one of the neighbors would barter services with us.

i work in industrial maintenance so i am familiar with hydraulics, mechanics and electrical, just not the intricacies of the tractors lol.

i plan to make a grab attachment to replace my bucket, but that will be a little down the road lol.. .

EDIT looking like i may add a 2 valve for the rear attachments separate and replace the 2 valve setup on the loader with the 2 valve..