Looking for recomadations!

resq2piper · Jun 11, 2020

Hi guys,
Looking for some help/suggestions. Our 1978 Case 580C backhoe has a thumb that is operated by a floor mounted slave cylinder (see pics). Well its is not functioning even after flushing the system, which is pretty basic...push pedal down, slave moves valve in to divert hyrdo fluid to move thumb into position, remove foot and rod is pushed back into cylinder. We believe it is an aftermarket thumb and there is no marking on it.
My question to you all is, Can I change out the hydraulic actuator one mounted at the diverter valve to an electric solenoid? and if so, any recommendations or links to what I could use. I can weld/retrofit a new mounting bracket if need be.
Thanks everyone for the all help.

oldnslo · Jun 12, 2020

A question: On the main directional valve, does it just move between two different positions too open and close the thumb or can you position the thumb partially closed I.e.three positions ?

If just two positions A possible suggestion to go electric is a linear actuator to replace the existing slave cylinder system. Just have to figure force required and stroke length.

If three positions you would have to connect the linear actuator to the main spool so it could both push and pull.

Other option would be to replace the complete valve assembly with a solenoid operated valve.

resq2piper · Jun 12, 2020

oldnslo said:
A question: On the main directional valve, does it just move between two different positions too open and close the thumb or can you position the thumb partially closed I.e.three positions ?

If just two positions A possible suggestion to go electric is a linear actuator to replace the existing slave cylinder system. Just have to figure force required and stroke length.

If three positions you would have to connect the linear actuator to the main spool so it could both push and pull.

Other option would be to replace the complete valve assembly with a solenoid operated valve.

Thanks for the reply oldnslo.
,It is just a two position, push pedal down, slave pushes rod out which in turn push the rod into valve (I guess changing where the fluid goes) to thumb while holding pedal down, relise pedal, fluid goes back to operate bucket curl. When I need o retrack thumb push pedal, use curl control to bring it back to home postion.
As far as force required, i can push the rod into valve by hand while my wife deploys or retracks the thumb for me.
As for linear actuator that is my thinking, was just looking for links to something someone might have used....guess I'll surf some more this weekend and try getting ahold of a real person to talk to.

Dave M7040 · Jun 13, 2020

If I understand your description of the operation of the thumb, one control on the backhoe is operating the bucket curl and the thumb movement and the foot pedal just selects between the two desired actions.

The foot controlled valve is just a selector allowing you to choose between two different hydraulic circuits with the flip of a switch.

I am understanding you correctly, this is the same situation loader owners have when installing a grapple on the loader bucket. The simplest way to do this is with a 12 volt selector valve.

This type of valve is sold in a number of places. This is a link to an Amazon seller.

Amazon.com: Buying Choices: Hydraulic Solenoid Selector/Diverter Valve, 13 GPM, 12v DC

Dave M7040