BX25D 3PH Splitter Problem

[macguyver13]

Hi all,

I'm still relatively new to this tractor stuff (but am loving it so far). Recently I bought a 3PH log splitter and hooked it all up to the back of my BX25 using the hydraulic connections used by the 3PH itself when the backhoe is not attached. I run the short hydraulic hose to the splitter and from there back to the inlet port on the tractor. That has allowed me to raise/lower the splitter (the splitter is open center) while it is attached. I have used it a couple of times now and it worked great (if a little slow due to gpm of BX25 but fine with me).

However, the last time I tried it I was moving a pallet with a bit of wood on it using forks on my bucket (thanks BXpanded) which was fine except that I noticed that when I lifted the bucket with the load on it, the log splitter started moving on its own! Under very little load it is fine, but if I have to fully deflect the FEL control to get it to raise, the splitter starts moving (as if to split wood, not retracting).

Now I'm new to the hydraulic game, but if it's an open center valve, shouldn't the fluid just flow through the splitter (no matter what PSI) and back into the tractor? Why would additional pressure trigger the valve to move one way (and not the other)?

Hoping I haven't done anything that seriously injures my tractor, but I'm wary to use it again until I have an idea what's going on. Any ideas?

Thanks in advance for helping me out even if it's just to set me straight on the hydraulics (again, just using the connections used by the 3PH on the BX25, not the 3rd inlet which returns to the reservoir I believe).

 

[kennyd]

Try adjusting the position of your rockshaft/3PH lever some, it sounds to me like its not closing the flow to the 3PH all they way so your 3PH and FEL are essentially both trying to operate at the same time.

 

[CHDinCT]

First off, the connections you're using at the rear of the tractor for the splitter are for the backhoe, not the 3PH. I'm not sure what your issue is - have to think about it some more, but I used to have a 3PH wood splitter that I ran off of the backhoe connections on my BX25 with no issues. I can tell you that the order of flow on a BX25 is pump -> backhoe -> FEL -> 3PH. So the splitter is taking the place of the BH and see's pressure before the FEL does. Not sure if that helps, but thought I'd throw it out there. I agree that with the splitter in neutral, it shouldn't move without the lever being pulled. Strange.

 

[CHDinCT]

Just to add: the only thing that comes to mind is that the exahust port on the splitter valve is a low-pressure port normally since the only oil flowing through it is normally just going back to the tank. But, in your case, with the splitter in neutral, full pressure is flowing to the FEL valve and when you use the FEL under load, there must be back-pressure in the splitter exhaust port. Maybe this "high" pressure is somehow back-feeding into the splitter cylinder and making it move?

 

[Stonehaller]

I can tell you that the order of flow on a BX25 is pump -> backhoe -> FEL -> 3PH. So the splitter is taking the place of the BH and see's pressure before the FEL does. Not sure if that helps, but thought I'd throw it out there.

If CHDinCT is correct about the order of the flow, then you should not be using the loader with the splitter connected unless your splitter has a power beyond port (you would need five lines on the valve, two to the cylinder and three to the tractor, inlet, tank and power beyond). It probably does not have the power beyond so you are using the splitter tank line as a power beyond to power the loader. The tank port is not designed for high pressure and internal leakage in the valve is pressurizing both side of the cylinder when the tank port is pressurized, causing the splitter cylinder to extend. You could leave the splitter on the three point, but just disconnect the hydraulic lines and put your loop connection back as you would normally with the back hoe off when you need to use the loader.

 

[macguyver13]

Apologies for not being clear on those connections on the rear. I meant that I was using the connections which make it possible to use the 3PH as I believe it states in the manual that if you disconnect the backhoe and don't connect that short line to the other side you won't be able to use the 3PH. I'll have to double check to see if my memory is correct on that one.

As for the hydraulics in general, I have a couple of follow up questions:

1. Based on Stonehaller's response, does that mean the backhoe of the BX25 has a power beyond port on it? I know there is one on the tractor.

2. Is the pressure in the hydraulic line the same (or roughly the same) all the time? I mean isn't the pump generating peak PSI all the time and that is fine since when there is no load on an open center system the fluid just flows through all the vales? Or does the PSI rise when one of the valves is deflected causing resistance?

3. Even if the splitter cylinder is getting pressure due to a leak in the valve, why does it always move the piston in one direction? I would think that maybe as the piston reached the middle of the cylinder the pressure would equalize or cause the valve to move the other way. I'm still not understanding what could make that valve move at all. It seems that even with 100x the pressure both sides of the valve wall would be seeing that pressure equally and therefore not deflect at all, but again, I'm new to hydraulics.

Thanks for the help so far, you've all got me thinking.

 

[Stonehaller]

1. Based on Stonehaller's response, does that mean the backhoe of the BX25 has a power beyond port on it? I know there is one on the tractor.

I am not familiar with how the BX25 is piped. I based my response on CHDinCT comments.

2. Is the pressure in the hydraulic line the same (or roughly the same) all the time? I mean isn't the pump generating peak PSI all the time and that is fine since when there is no load on an open center system the fluid just flows through all the vales? Or does the PSI rise when one of the valves is deflected causing resistance?

The pressure will vary depending upon the amount of work you are asking it to do. The pressure will be quite low if all valves are centered as the pump volume is just being circulated. Maximum pressure is determined by the relief valve. Pump volume or flow will be essentially constant at a given engine RPM. As you raise your loader, the pressure will only go high enough to move the loader cylinders. If you try to lift something heavier than your loader can lift, the pressure rises to the relief pressure. The pump volume stays the same, it is just going over the relief valve as the pressure is not enough to move the cylinders.

3. Even if the splitter cylinder is getting pressure due to a leak in the valve, why does it always move the piston in one direction? I would think that maybe as the piston reached the middle of the cylinder the pressure would equalize or cause the valve to move the other way. I'm still not understanding what could make that valve move at all. It seems that even with 100x the pressure both sides of the valve wall would be seeing that pressure equally and therefore not deflect at all, but again, I'm new to hydraulics.

If you equally pressurize both sides of a single rod cylinder the side without the rod has larger piston area and thus can overpower the rod side and the cylinder will extend.

 

[Stargazer]

IIRC if you don't connect the 2 back hoses together either direct OR with a open ctr valve ie splitter you deadhead pressure and it will squeal/relief v open

 

[CHDinCT]

Was thinking the easiest solution would be to just disconnect the splitter and plug the backhoe connections together when you want to use your fel for any real work. That or maybe look into a different splitter valve. By the way, what 3PH splitter are you using?

 

[macguyver13]

Thanks for the replies.

The splitter I'm using is a CountyLine splitter I got at Tractor Supply. Comes pretty plain so I had to get the hoses and connectors for it to hook it up. I guess since they are quick connect I could disconnect the splitter while using the FEL, I just figured it should have worked so maybe there was something I needed to understand.

As for the other comments on why the cylinder might move under pressure I have the following observations. I can see the logic in the larger surface area allowing more pressure, but the handle which controls the valve actually deflects so I don't think I'm just dealing with a leak in the valve. If fluid was just getting past the valve seals I could understand, but the handle moves as if someone was standing there operating it as if trying to split a log. Pretty crazy.

Well, unless someone has any other great ideas, I'll probably just disconnect it when not actively using it for now. Maybe someday when it needs an overhaul I will look at getting another valve for it so it will work correctly, but for the cheap splitter (~$700) I'll just continue using it until it dies.