BH77 - has anyone considered converting mechanical thumb to hydraulic?

[bandit67]

Title says it all.

I realize it may be an involved & expensive modification, but has anyone seriously considered doing this?

I can probably think of more cons to actually pulling it off, but not being a hydraulics expert, I know it's possible, but is it even worth further consideration?

 

[Monster5601]

Title says it all.

I realize it may be an involved & expensive modification, but has anyone seriously considered doing this?

I can probably think of more cons to actually pulling it off, but not being a hydraulics expert, I know it's possible, but is it even worth further consideration?

I think yes. In fact, I posted the same question a while back (albeit for a BH76) but didn't get any response. I would like to convert my thumb to hydraulic simply because of the way I use it which is mostly (these days) picking up and bucking trees. It is a matter of convenience and want, I've found ways to work around a fixed position thumb.

 

[Gasifier]

That would be really cool. I would love to do that to mine. I see they have a hydraulic thumb on some of the new Kubotas. Trying to remember what model it was.

 

[PAPPASMURF]

If I am correct (and I think I am) my dealer offered me a mechanical thumb or hydraulic thumb on my bh77 when I bought it in 2011. I didnt get either one (had already went over budget) but later after my purchase became interested and did research to find that it is offered and is pretty beneficial to those who would use it alot. Wish I had just a mechanical one myself! :confused3:

 

[wdchyd]

Knowing the kind of damage that can happen to hyd thumbs, I elected to spare myself the trouble to modify my mechanical one.....If I was relying on using it for work (which I don't) then a hyd thumb conversion would be on my christmas list

That said, I love the mechanical thumb....:thumbsup:

 

[bandit67]

The smallest hoe that a hydraulic option is offered on from Kubota is the B26 commercial TLB, though it is close in size to the BH77. The BH77 is ONLY offered with a mechanical option. However, I'm sure there are a few dealers out there that move enough of these units that will do an in-house hydraulic modification for their customers.

I certainly am happy to have a good quality thumb on my hoe, after not having one on the BH75 ( I got rid of a Brotec thumb that I hated), but I have used hydraulic thumbs on mini-ex's, and they are incredibly handy, which is why I wouldn't mind doing a conversion at some point. The nice thing about the hydraulic thumb is you can use it at any time without having to get off the machine to set the thumb in place and then retract it by hand, especially if you're wanting to just move one thing in the middle of a task.

 

[PAPPASMURF]

bandit....you are correct. I have seen them on a BH92, and I'm pretty sure that my dealer said that the bh92 hydraulic thumb could be made to fit the bh77. wish I had one....I am trying to convence Santa that I have been good enough this year to warrant getting one under my tree!:laughing:

 

[Gasifier]

Yes. I used a rented Kubota excavator with a hydraulic thumb for a weekend. Man can you get a lot done with a machine like that. I do not understand why they do not offer it on just about everysize tractor that is a little larger. I mean if you can get it on a B26, which I looked at the other week as well, why not one a larger tractor? Oh, the B26 was about $38,000. I saw one sell on e-bay a while back that went for something like $17,000. Company had used it for one job they had and put 1500 hours one it. It looked like it was in beautiful condition.

 

[SSdoxie]

Mounting a cylinder to the thumb is not a major problem, just need to identify overall retracted and extended length and go from there. The BIG hurdle is a valve to function it with. If there is no auxiliary lines or auxiliary valve on the Backhoe, it would need to be added. This would be comprable to adding 3rd function to an FEL. The valve would need a circuit relief in it for the base end of the cylinder, probably about 1/2 the Backhoe pressure relief, so if the bucket was forced against it too far the cylinder rod can push back/retract to keep from bending the rod.

 

[CDN Farm Boy]

I have every intention of modifying mine to hydraulic. While the mechanical one is certainly better than none, I find myself either getting on and off too much to adjust or having to bat things around with the bucket to get it just right to pick up.

I got a 2 x 8" ram that will fit perfect once I cut off the cyl base end and re-weld it 90 deg so the ports will stick out the side. No aux lines to power it so I'll likely just run lines to one of my spare remotes. I can't find anywhere on the boom that I like to mount a diverter valve. I figure having to reach by my left hip to activate is still WAY better than having to get off to move the pins. It will mean an extra pair of lines to connect but a diverter valve would need wires so to me that balances out.

 

[bandit67]

I thought I'd talk to someone like WR Long to see if they could come up with an electric-over-hydraulic setup like they have for the FEL remotes. They add a hyd block to the FEL block, so maybe something similar could be added to the backhoe hyd block. I'd like a switch setup that I could add to the backhoe bucket curl joystick, like on a mini-ex.

Actually might be a nice project for them to take on, since I'd bet they'd sell quite a few kits to owners of the smaller backhoes with mechanical thumbs. Worth a phone call, I guess.

If I was a hydraulic guru, I'd design & build my own setup, but since I'm not, it would ultimately be cheaper for me to just buy someone else's properly designed system.

 

[vic4news]

You might want to look at the Woods documentation for their mechanical to hydraulic conversion kit. Might give you some ideas of how you want to plump the valve.

http://www.woodsequipment.com/uploadedFiles/Products/Manuals/MAN0815.pdf

 

[Gary Fowler]

I have a B26 with hydraulic thumb and man is it handy. I like the foot control plate as it allows you to continue with full function of the hoe will closing or opening the thumb although it is a little cramped on the operator platform with the paddle folded out. I bought it used with 68 hours last June and have 220 hours on it now. The thumb is plenty sturdy and needs same hydraulic pressue as the hoe to operate correctly. Seems to me that one could splice in an extra block on the Hoe controls and run to the thumb control valve pretty easily. You will need to weld on some clips to hold the new hydraulic lines in place. The fingers on the thumb need to match up so that they fall between the teeth on the bucket not on top of them.

 

[CanuckPT]

If I am correct (and I think I am) my dealer offered me a mechanical thumb or hydraulic thumb on my bh77 when I bought it in 2011. I didnt get either one (had already went over budget) but later after my purchase became interested and did research to find that it is offered and is pretty beneficial to those who would use it alot. Wish I had just a mechanical one myself! :confused3:

I'm about to pull the trigger on a Bro-Tek thumb for my BH77. I'll let you know how it goes!'

 

[KubotaToy]

I let the dealer talk me into getting hydraulic thumb on my L45 which was already set up for it. Best money I ever spend!

 

[CanuckPT]

Nice! I wish it was in my budget!

 

[ericdube]

Have a read through this thread if you haven't already. If you can do it on a BX, then I'm sure it's definitely possible on a BH77!

http://www.tractorbynet.com/forums/kubota-owning-operating/144579-bx-hydraulic-thumb.html

 

[bandit67]

I'm about to pull the trigger on a Bro-Tek thumb for my BH77. I'll let you know how it goes!'

I hated that thumb on my BH75, and sold it within a couple months of getting it. The Kubota thumb on the BH77 is far superior. Still plan to eventually convert it to hydraulic.

 

[My Hoe]

Knowing the kind of damage that can happen to hyd thumbs, I elected to spare myself the trouble to modify my mechanical one.....If I was relying on using it for work (which I don't) then a hyd thumb conversion would be on my christmas list

That said, I love the mechanical thumb....:thumbsup:

wdchyd,

Can you please expand on this statement: "]Knowing the kind of damage that can happen to hyd thumbs, I elected to spare myself the trouble to modify my mechanical one....." Just never heard of any issues, other than if you try to put a thumb on a bucket where the teeth don't "mesh" between the two, then you can bend parts, I'm told. In other words, as Gary Fowler, said, above: "The fingers on the thumb need to match up so that they fall between the teeth on the bucket not on top of them."

Curious as to what issues you've run into.

Thanks,

My Hoe

 

[wdchyd]

Not to poo-poo on anyones wishes to install one but realize I do cylinder rebuilding, and that includes damaged ones

Many bent rods (leading to scored barrels cuz the piston head cocked sideways internally) have been diagnosed back to the problem of induced load

Meaning a force pushing in to the thumb piston is greater than the hyd cylinder can survive from another source......the bucket curl.

The bucket curls larger displacement and leverage can put extreme forces while clamping down using the curl cyl, unless there is a relief setup to allow extra pressure to relax (ie:work port reliefs in the control valve) during curl cyl use

If the hyd thumb is properly installed, the thumb cyl should go back in when there is too much pressure.....not bend and self-destruct. Without the safety of the reliefs plumbed in to the base end of the thumb cyl, the pressure intensifies greater than the rated pressure of the cylinder (assuming the thumb cyl is smaller than the curl)

Ideally either work ports reliefs or sizing the cylinder large enough to match is my recommendation

I actually have no problem with hyd thumbs, just not on my machine, I don't make a living with it