Loader plumbing

[California]

In another thread ...

Only trying to help here....Hoye's install instructions are flat wrong. They are almost just incomplete, until they specifically say to bypass or plug the power beyond, which makes them down right bad. The outlet port on valves is not usually (i.e. almost never) rated for hydraulic pressure (500psi +). The way hoye sets it up, when the 3ph is used, the outlet port will be passing the hydraulic pressure to the 3ph. Eventually, the valve will fail to work properly, or worse, fail catastrophically. The power beyond is design to pass the pressure to the next service, and also adds another return hose for draining the loader cylinders (lowering a load).

Stay tuned this man is onto something PB and returns is the key words. :thumbsup:

Here's what Hoye recommends on their loader install page for plumbing a loader.

The loader is in series ahead of the 3-point lift. The 'out' line from the loader's valve goes to the tractor's 3-point input.

I went out and looked at my YM240 (US version YM2000). Its loader was presumably dealer-installed by a factory-authorized Yanmar dealer. (30 years ago when Yanmar had dealers here).

Mine is plumbed according to the Hoye diagram. US Yanmars had a 'divider block' just ahead of the 3-point input. To add an accessory, an internal plug is shifted in the block to route fluid out its lower connector and back in at the upper connector.



This install conforms to YM240 Operation Manual, p 41. "control valves of the implement should be used by connecting the control lines [note plural] to divider block of high pressure line."

My slightly later (US) YM186D has its divider block bolted to a port on the transmission. I found a loopback hose between the divider block's Out and In ports. Other evidence indicates a belly mower or loader was installed in the past. According to this tractor's Operation Manual there shouldn't be a load or loopback attached between the divider block input and output. See JCByrd's post below.



Neither tractor has a sump return line.

 

[kenmac]

Sorry I didn't catch that. Mark told me that some yanmars ( don't know if he was talking about us mods or not ) had an adapter T at the hyd fill port & a seprate return line was run to this adapter T

 

[JCByrd24]

California, My dis on Hoye's install is merely the lack of a power beyond valve, and their specific instructions to ignore it if you have it, which is by all means incorrect. Your post here is a very good heads up to domestic Yanmar owners that the Hoye instructions need not apply (cutting into HP lines), because they're designed to do that with the factory diverter block. Indeed my 186d w/ YFL 650 is factory plumbed through the diverter as per the very good instructions in the owners manual. Going back to my dis on Hoye however, my 186d owners manual also talks EXPLICITLY to the power beyond feature of the included loader valve and how the PBYD port is run back to the diverter (3ph), and an extra return line from the loader valve to sump. Your domestic factory loader installs should be the same, per the manual. The sump fitting may vary by model, mine tee's in on the left side of the transmission area.

 

[California]

...my 186d w/ YFL 650 is factory plumbed through the diverter as per the very good instructions in the owners manual. ... my 186d owners manual also talks EXPLICITLY to the power beyond feature of the included loader valve and how the PBYD port is run back to the diverter (3ph), and an extra return line from the loader valve to sump. Your domestic factory loader installs should be the same, per the manual. The sump fitting may vary by model, mine tee's in on the left side of the transmission area.

Thanks, you're right. I'm leaning something here. I looked at my YM186D Operation Manual and see that recommendation, that loader Out goes to the sump and PBY goes to diverter block 'In'. So my YM186D is plumbed wrong, the old-fashioned way, rather than as it should be according to its manual.

 

[kenmac]

California, My dis on Hoye's install is merely the lack of a power beyond valve, and their specific instructions to ignore it if you have it, which is by all means incorrect. Your post here is a very good heads up to domestic Yanmar owners that the Hoye instructions need not apply (cutting into HP lines), because they're designed to do that with the factory diverter block. Indeed my 186d w/ YFL 650 is factory plumbed through the diverter as per the very good instructions in the owners manual. Going back to my dis on Hoye however, my 186d owners manual also talks EXPLICITLY to the power beyond feature of the included loader valve and how the PBYD port is run back to the diverter (3ph), and an extra return line from the loader valve to sump. Your domestic factory loader installs should be the same, per the manual. The sump fitting may vary by model, mine tee's in on the left side of the transmission area.

The grey's don't have (as far as I know ) a diverter block. Just my opinion, But, they should be supplying the 3 PT with the PB function on their loader valve instead of the outlet of the loader valve supplying the 3 PT.I was lucky enough to have this inspection plate to use as a return for loader valve HYD fluid

 

[JCByrd24]

I think you must be right that the grey's don't have it (diverter block), otherwise you'd think hoye would use it. Hoye actually sells fittings to bolt to the pump discharge and hp line so you don't have to cut either.
Yanmar Tractor Parts: HYDRAULIC ADAPTER - ADD A LOADER / LOG SPLITTER
Whatever the method of tapping the high pressure, pbyd valves should be used for the loader AND any additional after that (grapple, TNT).

 

[winston1]

Sure don't lay any claim to being a hydraulic guru. My ym2002d loader is plumbed as per Hoye diagram, does not have a diverter block. Everything has worked fine for 3-1/2 years. My loader valve does not have a pb port. Is there any reason I need to re do things?

 

[Smoody]

reading this has me a bit confused as well, wondering if mine is correct and what affects will it have if done like the Hoye diagram, wish Aaron would comment on their instructions since this has been brought to light. im guessing by now if their method had an negative affect on the tractor it would have shown itself in all these years.

SO if a control valve does not have a power beyond port then Hoye's instructions are correct?

**update**
this is a good reference and helped me understand this
http://www.bare-co.com/files/hydraul2001/hy16.htm

 

[Car Doc]

Thanks California for starting this new thread and we should note US and gray market may very well have different systems time will tell, so what is working on a ym240 may not be the same as a ym2000.

I have always had this problem with my curl and it wont lift half the time w/o a pause half the time either.

I talked to Koyker about the curl (which was the only thing I was aware of that was lacking at that point) soon after I bought my tractor (and actually got someone that cares that time) and he flat said he would send me a new valve if the adjustment he carefully explained in detail didn't work I couldn't have asked for anything more.

It didn't change anything and I left it at that and have been living with it until now. And dont take it wrong the tractor is functional technically but after operating equipment most of my life I have a feel for hydraulics that are working properly no expert just have some experience at it.

I am no hydraulics expert but how can a HP line also function as a return? Having the loader valve in series puts the return back into the same HP line yes?

The way it needs to be logically (my logic ) is the loader valve is ran from a power beyond and the loader valve needs a LP return to allow the cyls to retract properly.

I called Koyker yesterday and talked to an obnoxious guy and did get a power beyond sleeve ordered (if I ever call there again and want a new loader or anything again and get this guy I will buy it from china) and I will post on here as soon as its plumbed in whether he is right or Hoye is right.

 

[Domush]

I'm still learning, so my eyes may be better for not being bogged down with bad experience or worse for not understanding something, but from this chair what Car Doc put in bold is they key part.

If your valve has no PB (high pressure bypass) port and you are using it in series prior to other loads, it better be rated for the same high PSI rating the pump puts out or your days of luck may come to an abrupt end in a blast of high pressure hydraulic fluid.

Every valve document I've read has low a PSI rating on the "out" portion, indicating valves without a PB should not be used in anything but single valve operations or with no downstream loads. It seems to me upstream loads will be safe, so if your non-PB valve is the last item in the series, you are fine, as the pressure only builds on the pump side of a currently-in-use valve.

As a side note.. What is a curl?