Hydraulic oil type for Yanmar 4220D

[Gary Fowler]

I have a Yanmar 4220D and bought all the operations manuals with it, but all the parts etc are in Japanese. Can anyone tell me the type of hydraulic oil it takes. Local parts houses either have AW 32 or JD303 equivalent. I have replaced it with AW 32 but have got to thinking that since Yanmar made some tractors for John Deere, maybe the JD hydraulic oil would more nearly match.
The filter screen stopped up on it with green slime and black jelly looking material and it took 3 oil changes to get it all flushed out, but now the hydraulics are jerky and slow and it takes a few minutes of circulation before it will lift the FEL. I have been advised by one of the Net members that the pump may be bad now. It was working good till the screen fouled,and I may have damaged it by letting it run with the screen stopped up. IT took me a while to find the screen to clean it. While the screen was stopped up, nothing worked and it would not move as the hydraulic clutch would also not engage.
ANY ADVICE on this. IF new Pump is needed, Where can I find a NEW one.

 

[Gary Fowler]

Come on guys, some one must know a bit about Yanmars

 

[dieselfuelonly]

Hi Gary,

I used a JD 303 equivalent oil in my Yanmar YM1401D tractor - that is what is recommended to run in MY TRACTOR - But I'm not sure bout YOUR tractor - so I'd do some research before I tried anything, but hopefully that may guide you a bit.

 

[DieselPower]

If the hydraulic oil is used for anything but hydraulics then you need some sort of UTF fluid. If your tractor has a hydraulic transmission, wet clutch or wet brake the standard AW32 (Anti Wear additive package ISO 32 viscosity) oil will not have the proper additive package. UTF fluids such as the JD 303 you mention have additional additives related to the friction disc found in other systems and also tend to be multi-viscosity instead of a single viscosity.

 

[Gary Fowler]

Thanks everyone. That may explain why the pump is failing. The Vietnam rebuild seller that I bought it from said they used AW 32 from O'Reilly auto parts. The tractor worked good for about 30 hours then started having problems. What got me to thinking that the oil may be wrong was my brother-in-law and his Yanmar made JD 750. His book says use the JD 303 and I thought well maybe my Yanmar needs the same thing. I am not sure what the difference is, since out of the can they look the same and weight seems to be the same although the JD fluid might thicken up with some heat.
I am thinking that I will have to replace the pump now and maybe do some flushing with diesel to try and get some more of the sludge out and then go back with JD 303 fluid. There is surely some more greenish sludge somewhere in the system because the Oil turns grayish green in just a little while of run time. It hasnt been stopping up the screen, but it may be stopping up the filter. I wonder if this could be the problem with slow operation. Those filters cost me $30 each from Howe after shipping cost added and I have already went through 3 plus the original on the tractor.

 

[DieselPower]

If its a grayish color the problem could be you have some water in the tank? If water has gotten into the hydraulic tank then the fluid will start to turn milky in color.

 

[Gary Fowler]

It is not water in the tank. I reached up in the hole that the filter screen fits into and pulled out at least a half cup of grey/greenish fine powdery sludge. I cant figure where this would come from to start with even with working this tractor in rice fields it should not get this amount of dirt in the hydraulic system. The engine uses absolutely no oil so it seems to be in good shape, but the hydraulics is really starting to PO me with continually stopping up and messing up my pump. I wish there was some way I could power flush it with a solvent that would get all the sludge dissolved and then start over with fresh JD 303 oil and filters and a new pump.

 

[California]

Does that thing have wet brakes? Could that be brake pad fiber, or 20 years of wear residue from the shuttle shift clutches/bands/whatever?

It seems to me that power flushing is the only way to get it out.

I think I've seen long air wands that have a second tube to siphon from a solvent bottle. Does anyone know where to get one? Maybe a transmission shop would have the right flushing tools.

 

[DieselPower]

If it's solid particle contamination that's comming from fiber disc then changing the oil and flushing the system is only going to be a temporary fix. At some point things will start to slip if there not already. It might be time for a teardown and inspection to see what needs rebuilt.

 

[Gary Fowler]

I suppose it could be from disc wear but the material is not abrasive at all it fact it is quit slippery, like wet clay. The brakes and clutch work great with no problem. I guess it could be some sort of oil residue from the Japanese hydraulic oil that they used. Other than the grey color, it is similar to sludge from an old engine oil pan, just really heavy and really slick and slimy.
It appears to dissolve quite readily in hydraulic oil as the new oil turns grey/green in only a couple of hours of run time and possibly quicker, that is just the quickest time between drain/clean screen/ refill that I have done. The third drain and fill that I did, I found very little material on the screen, but I am thinking that the paper filter is much finer than the screen and must be stopping up. fI have put 3 new filters on it (each time I changed the oil) but it still acts the same way immediately upon start-up so I am confused about the suction being the issue
Question for you guys, if the hydraulic pump makes adequate pressure, just slow about doing it, could it still be worn out? OR is it just being starved for oil?