Woods 9000 BH - multiple piston movements?

[Jay4200]

My backhoe seems to only move one piston at a time. I haven't dug with it yet, but was playing around with the general movements the other day. When, for example, I pushed both control levers forward, I expected the primary boom to move down, and the secondary boom (where the bucket attaches - I don't know the correct buzz words) to swing out simutaneously. Instead, the primary boom didn't move unless I released the secondary. Bucket curl function was similar. Does this sound right?

I can't figure out how any smooth and controlled digging action can be accomplished if only a single degree of freedom can be used at once.

Thanks - Jay

 

[gizmo]

Are you running the engine at full rated RPM? What is the capacity of your hydraulic pump? Are you using a PTO pump?

It sounds like you are starved for hydraulic flow. At low flow the fluid will travel into the cylinder of least resistance.

 

[tawilson]

This has been batted around before some. When I first got my 758c I thought the same thing when practicing before digging. I found that once I actually started using it, it worked better. Maybe the resistance of digging helped. And they are very sensitive. If you are used to a bigger machine, you'll find these small backhoes very touchy. Especially the swing. I've got over a hundred hours on mine and still have to watch the swing motion. Oh, it's called a dipper.

 

[Jay4200]

</font><font color="blue" class="small">( Are you running the engine at full rated RPM? What is the capacity of your hydraulic pump? Are you using a PTO pump?)</font>

No, running only at ~1500-1800RPMs, don't know (but it's a 42HP machine, so I doubt it's flow limited, other than running at low RPMs), and no, the BH is connected to a single remote. I noticed these things while just moving the BH around, not actually working it.

</font><font color="blue" class="small">( It sounds like you are starved for hydraulic flow. At low flow the fluid will travel into the cylinder of least resistance. )</font>

I agree - that is what it looks like, though when the cylinders stop, they really stop dead, which strikes me as odd, but maybe that is normal too. If hydraulic flow is non-linear with RPM for some reason, then I could very well be running in a completely starved situation. I also suspect that my tractor is due for a hydraulic fluid cylinder filter change - I have the filter but haven't gotten to it yet - maybe that will help.

thanks - Jay

 

[Jay4200]

</font><font color="blue" class="small">( This has been batted around before some. When I first got my 758c I thought the same thing when practicing before digging. I found that once I actually started using it, it worked better. Maybe the resistance of digging helped.)</font>

I could see how digging resistance would help equalize things if it is a flow limitation, as per the previous poster. Cranking up the RPMs to actual work levels will probably make a big difference too - at least I hope so.

</font><font color="blue" class="small">( And they are very sensitive. If you are used to a bigger machine, you'll find these small backhoes very touchy. Especially the swing. I've got over a hundred hours on mine and still have to watch the swing motion. Oh, it's called a dipper. )</font>

I've found bucket/boom movements to be awfully slow (though running at 1/2-2/3 PTO speed), but I'll agree with the swing comment. I thought I was going to flip my tractor over the first time I swung the BH - and that was running just above idle /forums/images/graemlins/wink.gif.

Which part is the dipper?

Thanks - Jay

 

[tawilson]

The part attached to the bucket is the dipper. I wasn't clear by what I meant by touchy, and my comment about the swing was even more misleading. I'm also referring to getting more than one function at a time. And I still don't know how to describe it. I know just applying full flow to two different cylinders won't get them both moving. It seems like the one nearest the inlet gets the most power. It took me a while to get enough control to get things moving smoothly. Then bingo, it reached a point where it felt just like reaching out with my hand and scooping. Even now, if I'm don't use it for a while, it takes some practice to get back to that point. I probably didn't make any sense. If anybody here knows what I'm talking about, feel free to translate. /forums/images/graemlins/confused.gif

 

[CTyler]

Hi Jay, got your PM.

I'm running my 9000 on a L3130 from the tractor remote. The tractor hydraulic is rated at 8.3GPM. I can run multiple functions at the same time and do it on a regular basis. The only time there is an issue is when running at low RPM like a high idle. The BH only has single functions at low rpm due to low hydraulic flow and this is expected.

It sounds like your hydraulic flow is being limited some way.

 

[JASTN70D]

I am running the 9000 on a 70HP with 16GPM

If I do not "feather" the controls one will dominate the movement or oil flow and show the same symptom. This is normal

The idea is to ease open the valves enough to get movement without diverting the entire flow to the single movement or valve so that you share the flow between the 2 valves you want to move.

I think this is why under load it works better as the fluid stops flowing to one valve and starts out to the other open when you reach bypass.

In fact this feathering is what you must master to make you a good BH user. with 16GPM If I do not divert some flow to another valve or movement I can move to fast to control the movement I want. This is hard to explain but easy to understand when you do it

Try it out and let us know

 

[Jay4200]

</font><font color="blue" class="small">( The only time there is an issue is when running at low RPM like a high idle. The BH only has single functions at low rpm due to low hydraulic flow and this is expected.)</font>

OK - it sounds like everything was operating as expected for the RPMs I was running. Thanks for the inputs.

What kind of RPMs do you usually run? Full PTO or a little less?

Jay

 

[CTyler]

PTO is 2600 rpm and BH gets run at 2200-2600 RPM. More often than not its at 2600. When I first got it and was learning I ran it around 1800-2000. Once you get a feel for the balance points on the controls you bump up the rpm pretty quick.