YM2000B Trans/Hydraulic Filter Screen Help

[farsidejunky]

After draining the trans/hydraulic fluid, I pulled the filter screen for cleaning, and it had a few small tears. I had one as a back up, and when I compared the two, there are enough differences for me to seek outside help before installing this aftermarket screen. Dimensions are the same on both the screen and the base plate.

Differences:

1. The old screen was held together by a nylon lock nut, and further secured by a cotter pin through the stud. The new one has three flimsy tabs that hold it together at the base plate.

2. The old one has two o-rings; one in the exact same place as the new one, and one closer to the base plate. It appears the second o-ring is for sealing the system, but I could be wrong. This brings me to 3.

3. No gasket on the base plate. Should it have had one? I see it available from Hoye parts, but this tractor did not have one.

Images below. Thanks in advance for any clarification you can lend. Cross posted to another forum as well.

View attachment 658790
View attachment 658789

 

[rScotty]

Your attachments didn't.
Posting photos to TBN is an archane art. But you start by selecting "Go Advanced" rather than "Post Quick Reply". Once in "Advanced", go to the bottom and click on "Manage Attachments". That brings up a screen that allows you to " Add Files" in the upper Rt. hand corner. You chose "Add Files", Select" a file or photo on your computer's main directory, and then once selected you can "UpLoad" the file or attachment.
So the selection sequence is: Manage Attachments/Add Files/Select Files/Upload/Done.

Back to the filter, Yanmar made several versions... and since your tractor is not new there is no way to know what you have. For instance is the screen nylon or steel?

But it is a simple crud filter in the suction line. All you want that cleanable filter to do is prevent large particles from being sucked into the next stage - which is either a spin on hydraulic replaceable can filter or the hydraulic pump itself depending on model.

So poke around with a flashlight and see what good the O rings do. Try to improve on what you have. Generally at the far end of the filter the filter itself will neck down to some sort of protrusion that fits into a hole in the casting at the far end. No real sealing needed there, that's just to locate it. but sometimes tricky to get it fitted into the locating hole. I've missed it myself & ended up squashing the filter. So get it insterted right into the far end, and at the near end by the 3 bolt flange, you should see how an O ring will help locate the filter in the casting. Basically you want the filter to suck oil through it's screen without letting (much) crud past the ends and into the suction line.

Keep in mind that Yanmars are simple.

As for the gasket, it helps to have one so that joint doesn't leak. Absolutely NO LEAKS to the outside world are allowed there, because if it does leak oil out that flange when sitting, it means it can also leak air into the suction line while running. And air in the suction line causes cavitation in the hydraulic pump which tears up the pump ... eventually.
You can make the gasket yourself out of any gasket paper. Or if you are an artist with silicone gasket sealer and can discipline yourself to paint only the very thinnest layer of sealer on and then let it surface cure before mounting (takes half an hour to an hour) then you can use any silicone gasket sealer. But please, do NOT goop it on or assemble when the silicone is still wet. You don't want stringers of silicone in the hydraulic system.

As for the tears in the filter itself, you can sew the edges together if you have a thread that will stand up to hot oil. Or patch it.... I've used 200 mesh stainless steel screen from the hardware store. AbsolutelyNo tape allowed, though.

And after you get frustrated enough patching it, consider ordering a new one from Hoye for the next go-round. As long as the flange doesn't leak, your tractor will survive in the meanwhile. Oh, might as well get a couple of gaskets, too. Not that you can't make a filter yourself.... but his are better...
enjoy,
rScotty

 

[farsidejunky]

Your attachments didn't.
Posting photos to TBN is an archane art. But you start by selecting "Go Advanced" rather than "Post Quick Reply". Once in "Advanced", go to the bottom and click on "Manage Attachments". That brings up a screen that allows you to " Add Files" in the upper Rt. hand corner. You chose "Add Files", Select" a file or photo on your computer's main directory, and then once selected you can "UpLoad" the file or attachment.
So the selection sequence is: Manage Attachments/Add Files/Select Files/Upload/Done.

Back to the filter, Yanmar made several versions... and since your tractor is not new there is no way to know what you have. For instance is the screen nylon or steel?

But it is a simple crud filter in the suction line. All you want that cleanable filter to do is prevent large particles from being sucked into the next stage - which is either a spin on hydraulic replaceable can filter or the hydraulic pump itself depending on model.

So poke around with a flashlight and see what good the O rings do. Try to improve on what you have. Generally at the far end of the filter the filter itself will neck down to some sort of protrusion that fits into a hole in the casting at the far end. No real sealing needed there, that's just to locate it. but sometimes tricky to get it fitted into the locating hole. I've missed it myself & ended up squashing the filter. So get it insterted right into the far end, and at the near end by the 3 bolt flange, you should see how an O ring will help locate the filter in the casting. Basically you want the filter to suck oil through it's screen without letting (much) crud past the ends and into the suction line.

Keep in mind that Yanmars are simple.

As for the gasket, it helps to have one so that joint doesn't leak. Absolutely NO LEAKS to the outside world are allowed there, because if it does leak oil out that flange when sitting, it means it can also leak air into the suction line while running. And air in the suction line causes cavitation in the hydraulic pump which tears up the pump ... eventually.
You can make the gasket yourself out of any gasket paper. Or if you are an artist with silicone gasket sealer and can discipline yourself to paint only the very thinnest layer of sealer on and then let it surface cure before mounting (takes half an hour to an hour) then you can use any silicone gasket sealer. But please, do NOT goop it on or assemble when the silicone is still wet. You don't want stringers of silicone in the hydraulic system.

As for the tears in the filter itself, you can sew the edges together if you have a thread that will stand up to hot oil. Or patch it.... I've used 200 mesh stainless steel screen from the hardware store. AbsolutelyNo tape allowed, though.

And after you get frustrated enough patching it, consider ordering a new one from Hoye for the next go-round. As long as the flange doesn't leak, your tractor will survive in the meanwhile. Oh, might as well get a couple of gaskets, too. Not that you can't make a filter yourself.... but his are better...
enjoy,
rScotty

Thank you for the detailed reply. I need another post past this one to post links. I will be there shortly.

Silicone artist? Unfortunately, I am the type that later finds it in my hair, so no...lol. Sounds like a paper gasket cut out is more my speed or wait on one from Hoye.

As for my system, if has no external can filter. Just the screen.

Your point about leaks and cavitation in the pump is concerning to me because there is also a leak from the top of the transmission as well. I can't tell if it is the boot or the gasket under the shifter mount plate. Will that also cause cavitation?

 

[farsidejunky]

3rd post.

(Sorry mods).

 

[farsidejunky]

Here are the image links.

Slide1 — ImgBB
Slide2 — ImgBB

 

[rScotty]

There isn't any cavitation from leaks on top of the transmission, as long as they are either above the level of the trans/hydraulic fluid or far enough away from the level of the suction filter that air bubbles would rise up and dissipate before being sucked into the suction line. So no...there's no problem with air or cavitation from air that is connected with leaks into or out of the top half of the transmission. The top of the transmission is filled with air at atmospheric pressure anyway, or should be.

There is a problem with leaks at the top of the transmission, and that is because that Yanmars were prone to leaking rainwater/rice paddy water into the wrong places. Odd, but apparently true. They built one of the best little tractors on the planet and then didn't pay enough attention to the fact that it was poorly designed to be used in the wet.

All of the following places are know to pass outside water into the oil, debasing the oil. Into the transmission past the shift lever boots, into the steering box via the steering wheel center draining down the shaft shaft, and into the fuel tank past the gasket in the fuel cap fuel gauge. into the transmission vent pipe, into the rear end vent pipe - usually behind the seat, and also into the right and left brake housings. The poor venting can be improved by making larger vents with extension tubes facing down. And of course parking it out of the rain fixes all these things.

Water in the fuel you may be able to see at night with a flashlight (water in diesel fuel is sometimes faintly luminous). Water in oil makes the oil milky rather than amber clear.
rScotty

 

[rScotty]

Here are the image links.

Slide1 — ImgBB
Slide2 — ImgBB

Congrats on the attaching the photos.

The new one doesn't need a nut; it is spot welded. You can see the discoloration of the welds. The threaded rod and nut on the old one allows you to replace the SS filter cloth. That is typical thinking of old Yanmar designs to make the original part both reusable and repairable - part of the reason they are still popular tractors. SS filter cloth is inexpensive compared to buying a complete filter. Having two O rings is again typical Yanmar overkill on their original rebuildable/reusable components.

By modern design standards, one O ring and a gasket should be enough to do the job.

rScotty

 

[California]

That o-ring at the shoulder seals the unfiltered sump side, from the cavity containing clean oil that will be sucked to the hydraulic pump.

Your new filter matches the original and replacement filters in my YM240 (YM2000).

I've found a thin, and dried, bead of silicone sealer on the triangle plate is sufficient for sealing the plate so the sump doesn't drip to the ground. Your lower o-ring would be more convenient for periodic maintenance but this bead of sealer does the same thing.

Your used filter doesn't look bad. Here's what real neglect looks like!

When I bought the YM240 in 2003 I spent a month correcting a lot of severe neglect. This filter was strongly cemented in place and I tore it getting it out. The o-ring at that shoulder was wrong, it was too fat so the metal part got dimpled, and it was made of something that became hardened glue.

I got a new filter from Hoye, flushed the transmission with diesel and wiped out crud from the sump with a rag, and put in fresh fluid.

10 years later I replaced the hydraulic fluid a second time and the filter looked about like your used filter, it cleaned up easily. I took the filter out again last year for an axle repair. The filter and sump were pretty clean and the fluid looked pure so I rinsed the filter, wiped the sump, and re-used the 6-year-old fluid.

The hydraulic system has always worked properly despite its early neglect. Your used filter looks nearly pristine compared to what I found!

 

[CoyPatton]

I have removed my comment as it was well addressed by others as I later read. My comment concerned the cavitation and tip of tranny leak.
Great explanation rScotty. Yours was so spot on I removed mine!

 

[rScotty]

I have removed my comment as it was well addressed by others as I later read. My comment concerned the cavitation and tip of tranny leak.
Great explanation rScotty. Yours was so spot on I removed mine!

Coy, I saw it & thought your explanation was also spot on. Plus you said in a few words what takes me far too many.