Adding additional hydraulics

   / Adding additional hydraulics #1  

BruceWard

Platinum Member
Joined
Sep 28, 2008
Messages
850
Location
Central, AR
How expensive is it to add another hydraulic valve for a backhoe thumb on a B21? Do you have to go with dealer parts or can I used third party or used parts?
 
   / Adding additional hydraulics #2  
I think an electric diverter that uses the curl cyl circuit is the cleanest.
You do not have to run hoses all the way along the hoe boom.

Kubota sells AUX valves for the B21....they are actually made for Kubota
by Woods. If you go with manual AUX spool valves, aftermarket is fine
and a LOT less $ than buying OEM from Kubota. You can see pix of both
if you follow my links below.
 
   / Adding additional hydraulics
  • Thread Starter
#3  
I like the solonoid cutoff idea. Could you tell me more about the routing of the fluid. Did you hook up the bucket and the thumb in series or parallel? I dont see how it could work in series, but I thought hydraulics are supposed to be in series? I see how it could work in parallel.

Do you have any difficulty getting the thumb to return to the open position? I guess if you push the bucket against something the thumb will move regardless of bucket position.
 
   / Adding additional hydraulics
  • Thread Starter
#4  
Also, do you think a hydraulic thumb is worth twice the cost of a manual thumb. With your $40 cutoff suggestion I think I can buy and install a hydraulic thumb for <$800.

I have 50 or so stumps and hundreds of rocks to move this winter.
 
   / Adding additional hydraulics #5  
I like the solonoid cutoff idea. Could you tell me more about the routing of the fluid. Did you hook up the bucket and the thumb in series or parallel? I dont see how it could work in series, but I thought hydraulics are supposed to be in series? I see how it could work in parallel.

Do you have any difficulty getting the thumb to return to the open position? I guess if you push the bucket against something the thumb will move regardless of bucket position.

Go ahead and read my project description. But yes, the plumbing is in
parallel, which allows the thumb to perform more like a traditional grapple,
vs. a fully independent thumb. The bkt or thumb experiencing the least
resistance moves first. This is particularly valuable when picking rocks or
working near an immovable object. With an independent thumb, the force
acting against the immovable object will lift the tractor. Not so with a
parallel connection.

I operate my thumb to the fully open position to get it out of the way when
I am ready to return to dig-only action. I can turn off my solenoid valve with
the thumb in ANY position, which gives me the equivalent of a mechanical
thumb. An hyd thumb is much better than a fixed thumb, but the add'l costs
for pivots and hydraulics are quite significant. (See story.)

RE the B21, I offered a mech thumb kit to the guy who bought my B21, and
he said he wanted it, but he has never come back for it. I made 6 of these,
one of which I beefed up for my current hyd unit. The B21 has a very
similar dipper width to my Prairie Dog hoe.

I am using the same solenoid valve installation for my current 4-in-1 FEL
bkt project, which is only waiting on hyd fittings I ordered. I plan to post
a thread soon on that project.
 
 
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