BH77 - has anyone considered converting mechanical thumb to hydraulic?

[CDN Farm Boy]

Welcome.

You have come to the right thread to follow.

The only way to have the thumb work in conjunction with ALL the other functions is for it to have it's own valve independent of the rest. Factory B26 does this with a foot operated control valve. jim_wilson has a plan to tie in an aux valve to his system. With mine, I may cheap out and cheat by running another pair of lines to another remote on the tractor (valves are expensive up here in Canada). I'll have to reach by my left elbow to operate but still way better than getting off the machine to adjust. Diverter valve off the boom swing would be the other option -- use boom swing because the need to swing and thumb at the same time is all but non existent but curl and thumb can still be done together which would be the most common of dual operations.

 

[Gundawg]

My first thought were to T into the pressure and return lines with a double acting open center electric solenoid type valve relying on the existing bypass valve but I am not sure this will work.

You are saying this will not work is that correct?

 

[CDN Farm Boy]

You are saying this will not work is that correct?

If I'm understanding you right, you are thinking of mounting the new one in parallel with the existing? If that's the case, it won't work. The fluid will always pick the path of least resistance (whichever valve is open at the time) and nothing will work.

Valves need to be mounted in series, usually the PB port of the first used to power the second. The returns however can be T'd together

 

[CDN Farm Boy]

I got mine up and running last night and a quick test this afternoon. Woo Frickin Hoo! :cool2: Worth every bit of the time and $$.

2 x 10 cyl, 27' of 1/4" hose, some fittings and hose protector, all told, I'm into it for $250. All parts other than the QD's were from Princess Auto. I'd ordered extra male QD's when I did the remote install so I would have them available.

I cheaped out and ran them off one of my other pairs of rear QD's rather than a valve mounted on the BH itself. If I get fed up with having 4 hoses to connect and have an extra $500 burning a hole in my pocket I might switch but for now, I'm up and running. The only mods I've done that aren't easily reversible is to weld 2 mounts on for the hose clamps. If I ever needed to it would take me about 10 min max to remove this and put the mechanical linkage back on.

This is the cyl that will be replacing the mechanical linkage.


I have to cut the base mount off the cyl, turn it 90 deg and weld it back on and also narrow the head mount from 2" to 1.5". The base mount needs to be turned so the ports are on the side.


The ram was mounted and welded in place to ensure that the pin boss was perfectly in line with the cyl body.


The head mount needed to be narrowed to fit in the space of the old linkage


Lines were run on the outside of the stick and then go down inside the hole in the top of the boom


The width of the thumb actually provides some protection for the head port. Lines were plumbed direct to the ram, no QD's at this end as I never plan to use an auger etc.


The lines were fished thru the existing hose protector at the base of the main boom


I've got a 4 spool valve for remotes (3 rear, 1 future front) The BH is run off one pair with 3/8 couplers, the thumb is on the top 1/4" pair, easy to reach with my right hand by my left elbow.


Everything tucks in nice and tight from the operator's seat


If I leave the valve activated for the BH, I can still run the thumb but it is slow (flow is split between 2 open ports). If I neutral the valve powering the BH, the ram works nice and quick. This will give me incentive to order replacement detent kit that I lost the spring out of during install and have been using a cedar shim to hold open for now.

 

[CDN Farm Boy]

Any of you other guys getting close to having your's converted? I've got a few hours on mine now and love it. :cool2:

 

[trihounds]

I'm still waiting on my 3300 which is scheduled to arrive at the dealer mid Sept. Thanks to your advice, I killed the Kubota rear remote and upgraded the tires to the same as yours, which are now 'optional' on the 3300. I'll still have to do the hydraulic mod but I keep checking back to this thread for inspiration and to oogle over the machine.

 

[bumperm]

Bandit67,

Is there any more info on the kit from the company you were dealing with?

bumper

 

[bandit67]

I got busy this summer and communication with them fell off. They were working on it mainly for me and needed input from me, so probably shelved the project when they didn't hear back from me. I'll try to get back with them soon to see if we can get it back on track.

 

[bumperm]

Bandit67,

Thanks! I think there'd be a worthwhile size market for a well designed kit at a sensible price point.

bumper

 

[paulwestski]

The Kubota BH4948 valve kit comes with everything including the foot pedal and linkage for $850.00
You just would need the hoses, cylinder and of course the thumb.
If the BH77 valve mount box is not wide enough, could it be removed and widened slightly?