Ditching blade on Kub L45 backhoe

Vigo327 · Nov 16, 2022

I could not tell exactly what Stonehaller is referring to.

Is it possible for a valve set to have an 'impact relief' type of system built in where the work ports have access to a relief valve set higher than the 'normal' relief, for reason of bypassing to tank from impacts?

I know what a regular 'crossover relief' valve is but im under the impression it cannot be used with normal cylinders on which the two sides of the piston have different displacements, because it only hooks them to each other and that by itself would not allow the cylinder to move.

sd455dan · Nov 17, 2022

Russ Lanoie said:
Most backhoe as well as other controls only send fluid to bypass when the control is activated, which is why the first responder to this post correctly commented: Remember the hydraulic system control valves, lines and cylinders are not protected with relief pressure valves when external loads are exerted like that.
This is the reason for the chain...

.
A safety chain seems like a Very good idea, also as in the video a nice slow and controlled speed

I liked and enjoyed the video, a new spin on backhoe uses for sure.

Smokeydog · Nov 17, 2022

Have a friend who thought he discovered a novel way of yarding firewood logs by chaining to the B26 backhoe bucket and would swing and crowd the boom as needed thru the woods. The weight for traction and articulation helped drag to wood. I warned him to no avail. Didn’t take long for the control valves to begin leaking by. After repairs he didn’t do that way anymore.

Relief valves protect from pump side. Don’t protect from external forces because in use it shouldn’t have significant external force loads. Your chain helps minimize some of the external force on the hydraulic system.

The OP has considerable experience combined with the chain and careful use works well for him. Avoiding shock loads to the hydraulic system important. I like out of the box thinking. Sometimes you don’t know till you try. Again, thanks for sharing.

My gravel driveways are too steep, rocky and tree lined to utilize this technique without the possibly compromising the equipment. Plus over fifty years have improved equipment and techniques to maintain the roads.

Stonehaller · Nov 19, 2022

Vigo327 said:
Is it possible for a valve set to have an 'impact relief' type of system built in where the work ports have access to a relief valve set higher than the 'normal' relief, for reason of bypassing to tank from impacts?

That is pretty much correct. Work port reliefs are relief valves on the valve ports that go to the cylinder. They relieve pressure if an external force applied to the cylinder causes the pressure in the cylinder to exceed the work port relief setting. Very common on backhoes.