2005 Kubota MX5000 and Woods BH9000 hoe

[MX5000]

I have a 2005 Kubota MX5000 and not too long ago, bought a used Woods BH9000 backhoe attachment and subframe. I really like the backhoe, but like some others out there, would like to speed up the simultaneous swing, dipper, and boom functions. My tractor stats. show the tractor pump is 14gpm. I'm guessing about 6gpm is going to the power steering. I compared to other M series on the Kubota website. The others in and above my MX5000 size range jump to 17gpm pumps. I'm running the backhoe off a set of rear remotes I had installed. I could be wrong, but may have about 8gpm to run the hoe at PTO speed. If I feather really well, I can almost run everything at the same time, but is a little slow. I did some searches and noticed many of the PTO pumps for the backhoes were around 10gpm. Anyone have a Woods BH9000 with a PTO pump? Can you run everything simultanously at a quicker pace? I noticed the L48 TLB has two pumps for swing and dipper and boom functions (and a 26gpm pump). That's a pretty neat idea. Anyway, before I bought a PTO pump and tank, I wanted to know if it was worth spending the money. Also, I'm not a big fan of running the backhoe at PTO speed (or wide open throttle). It seems a little extreme just to run a backhoe just to get the maximum hydraulic pressure. Has anyone used a larger aftermarket PTO pump to run at a lower engine speed?

Thanks,
Howard

 

[MadReferee]

The MX 5000 has 4.8 gpm for power steering and 9.2 gpm for the 3pt and remotes at 2700 rpm. I am not sure what the Woods BH9000 requires for a minimum but 9+ gpm should be sufficient.

What you are experiencing is a fact of life for backhoes controlled by a single pump. The issue (it's not a problem) you are experiencing is due to the backhoe valve design. Fluid will flow to the spool of least resistance and if two spools are activated simultaneously then one spool will most likely get more than the other. As you pointed out, tractors like the L48 overcome this by having two or more pumps and valve blocks to control the various backhoe functions.

I would not spend money for the PTO pump setup because adding a PTO pump will most likely not resolve your issues with simultaneous function operation.

 

[MX5000]

Thanks Mad,
I appreciate the explanation.

Howard

 

[Bob_Young]

This question seems to be asked often, always with the same answer. One thing I've never seen addressed is whether it would be possible to split the hoe's hydraulic load between the onboard tractor pump and a PTO pump. Possibly dedicate the tractor pump to swing and use the PTO pump for boom and dipperstick.

My understanding of BHs is admittedly shallow, so there's probably a simple reason why this wouldn't work. If all the hydraulic controls work off a common hydraulic manifold, it would probably be a tough mod.
Bob

 

[MadReferee]

My understanding of BHs is admittedly shallow, so there's probably a simple reason why this wouldn't work. If all the hydraulic controls work off a common hydraulic manifold, it would probably be a tough mod.
Bob

It would be impossible. You can't have the spools of a single valve working from different hydraulic sources. You would have to have multiple valves with multiple hydraulic sources.

If you want a backhoe that operates multiple functions simultaneously, the only cosrt effective way to accomplish this is to purchase a TLB that has multiple pumps and multiple valve blocks for the backhoe (ie. an L48).

 

[Bob_Young]

OK, thanks Mad. That was my mistake. I didn't know the whole thing was controlled by a single valve; thought there was a separate valve for each motion.

Bob

 

[MX5000]

This question seems to be asked often, always with the same answer. One thing I've never seen addressed is whether it would be possible to split the hoe's hydraulic load between the onboard tractor pump and a PTO pump. Possibly dedicate the tractor pump to swing and use the PTO pump for boom and dipperstick.

My understanding of BHs is admittedly shallow, so there's probably a simple reason why this wouldn't work. If all the hydraulic controls work off a common hydraulic manifold, it would probably be a tough mod.
Bob

It's funny you say that Bob. When I started to reply to Mad, I had a big paragraph saying the same thing about using the rear remotes for the swing and a PTO pump and tank to work the boom and dipperstick. Once I got done, I started thinking about the cost and just deleted that whole part. When I was done, all that was left was pretty much...thanks, Mad.
I was thinking, my remotes were $800.00 installed. A PTO and Tank would be at least that. I'm not sure about how I could alter or split the spool valves. I may have to buy seperate valves. I'm sure it can be done, I'm just not sure it would be cost effective. Since I do a little work on weekends sometimes for an hourly rate, it would be worth it to me to get it working on two pumps. If nothing else, it maybe an interesting project.

Howard

 

[MX5000]

It would be impossible. You can't have the spools of a single valve working from different hydraulic sources. You would have to have multiple valves with multiple hydraulic sources.

If you want a backhoe that operates multiple functions simultaneously, the only cosrt effective way to accomplish this is to purchase a TLB that has multiple pumps and multiple valve blocks for the backhoe (ie. an L48).

The thing is, I was quoted about $50,000.00 for an L48. I still owe $14,000.00 out of about $30,000 on my MX5000 with loader and backhoe. If I could get it working on 2 seperate pump sources, it would work for me. I do see your point about seperate spool valves.

Howard

 

[john_bud]

It would be impossible. You can't have the spools of a single valve working from different hydraulic sources. You would have to have multiple valves with multiple hydraulic sources.

If you want a backhoe that operates multiple functions simultaneously, the only cosrt effective way to accomplish this is to purchase a TLB that has multiple pumps and multiple valve blocks for the backhoe (ie. an L48).

Mad,

When you say "impossible", do you mean at fulll 100% capacity? Or impossible at all?

My 1963 vintage hoe, with 1 pump for the tractor and loader, can run the dipper stick and bucket curl at the same time in some compacted soil and that is with feathering the boom up to keep the back wheels on the ground. I also use 2 or 3 (boom, swing, dipper and curl) at the same time when dumping a bucket. The pump is 23 gpm at 2200, but I usually run at 1700-1800 rpm rated pressure is 2000 psi.


The sales literature (like that can be believed!) states that multiple operations can and should be done simultaneously. Oddly enough, when using the FEL I have a hard time using the lift and curl at the same time.

Trying to learn more...
jb

 

[MadReferee]

Re-read the entire posted question by Bob_Young. He wants to take an existing valve block and connect two pumps to it, with each pump controlling different spools. That is impossible to do with the valve blocks that are used on typical CUT backhoes.

His problem is that when he tries to energize more than one spool simultaneously, the operations slow down to an unacceptable rate. This is normal with an internal design that puts the spools in parallel with the main flow. Fluid will be divided between the activated spools depending on which one needs more. Since gravity is not helping here like on a loader, you get weak/slow operation.

Lift/curl on a loader valve (usually the 7 o'clock position) is usually not supported for the above reason. All other multiple operations, lift/dump, lower/dump, and lower/curl have gravity to assist in one of the movements. This means more fluid/pressure can be applied to the operation that is trying to overcome gravity and the operations actually work faster.