Hydraulic functions problems

[MyAxleBroke]

My R400 backhoe attachment works very well. The only complaint.
The swing function doesn't have much power side to side, unless the boom is full up, holding pressure up and swing together plenty of power. Is this a design problem or something that is fixable?
It is a pain to full boom up all the time to get any swing with power.
Thanks for the help.

 

[fried1765]

My R400 backhoe attachment works very well. The only complaint.
The swing function doesn't have much power side to side, unless the boom is full up, holding pressure up and swing together plenty of power. Is this a design problem or something that is fixable?
It is a pain to full boom up all the time to get any swing with power.
Thanks for the help.

As I understand it, the hydraulic flow on many of these small BHs, is because the hyd pump is sharing flow with another function.

 

[TheOldHokie]

My R400 backhoe attachment works very well. The only complaint.
The swing function doesn't have much power side to side, unless the boom is full up, holding pressure up and swing together plenty of power. Is this a design problem or something that is fixable?
It is a pain to full boom up all the time to get any swing with power.
Thanks for the help.

Power or speed?

Dan

 

[MyAxleBroke]

Power or speed?

Dan

both

 

[TheOldHokie]

both

I dont know but thats odd. I think you need a WSM.

Dan

 

[MyAxleBroke]

As I understand it, the hydraulic flow on many of these small BHs, is because the hyd pump is sharing flow with another function.

I dont know but thats odd. I think you need a WSM.

Dan

I have 2 I looked and there isn't a section titled that's your problem.
lol thanks

 

[TheOldHokie]

I have 2 I looked and there isn't a section titled that's your problem.
lol thanks

No but there should be a section showing the hydraulic circuit(s). Then you noodle out the possiblities.

Dan

 

[Russell King]

I have 2 I looked and there isn't a section titled that's your problem.
lol thanks

They do have a trouble shooting diagram at the end of the section that could be helpful to at least eliminate some possible problems.

 

[torch]

The swing function doesn't have much power side to side, unless the boom is full up, holding pressure up and swing together plenty of power. Is this a design problem or something that is fixable?

Let me preface this by saying I have no knowledge of your specific model BH.

That said, it is common backhoe hydraulic circuits to be sized for different flow rates in some of the lines to balance speeds when using multiple functions at once. This helps the operator make smooth movements and prevents once function from robbing others of all the fluid.

Secondly, if your BH has a "open center" type hydraulic system, then the pressures in the system are near zero when levers are all neutralized. The pressure climbs when cylinders are operated up to the maximum relief valve setting -- as when a cylinder hits the end of it's travel.

I wonder if the swing function on yours is deliberately limited for smooth operation (and perhaps guarding against overstressing the boom when swinging against something) but the speed/power increases when another cylinder (in this case the boom) hits the end of it's stroke and increases the pressure to max?

 

[TheOldHokie]

I wonder if the swing function on yours is deliberately limited for smooth operation (and perhaps guarding against overstressing the boom when swinging against something) but the speed/power increases when another cylinder (in this case the boom) hits the end of it's stroke and increases the pressure to max?

That kind of ptotection is usually provided by port reliefs and I dont see any in the parts book.

Assuming the backhoe valve is a standard parallel type the pressure/flow goes to the least loaded spool in the set.

What we "know" is the pressure/flow increases when the boom cylinder is deadheaded. That suggests the boom circuit is somehow bleeding off pressure/flow.

A hydraulic circuit diagram would help immensley. Diagnosing this is going to tequire understanding oc the finer points of hydraulic Circuit operation.

Dan