Backhoe BT750B Auto return conversion to Manual

[Ken speirs]

Hello,
My Backhoe BT750B, off a B20 tractor, was smashed by a tree when stored for the winter and I've searched with the dealer for the replacement parts but the electrical parts for the auto return are no longer available. So I'm looking at options for converting it to a manual swing. Has anyone done this and can help point me to the right direction. Thank you

 

[PoTreeBoy]

Hello,
My Backhoe BT750B, off a B20 tractor, was smashed by a tree when stored for the winter and I've searched with the dealer for the replacement parts but the electrical parts for the auto return are no longer available. So I'm looking at options for converting it to a manual swing. Has anyone done this and can help point me to the right direction. Thank you

I assumed from your other thread that you had a burned out solenoid. As you say, parts are NLA from Kubota but that doesn't mean they're not available through other channels. For example, the solenoid coil may be 54077-5 from a Husco distributor.

Post a picture or two of the damage we're dealing with.

 

[Ken speirs]

Thanks for your response. Here are a few photos. the previous owner had troubles with the auto return , so I’m thinking of bypassing it completely or other alternative…. Just beginning
to learn and explore options. All feedback and advice welcome.

 

[PoTreeBoy]

Thanks for your response. Here are a few photos. the previous owner had troubles with the auto return , so I’m thinking of bypassing it completely or other alternative…. Just beginning
to learn and explore options. All feedback and advice welcome.

1. I'd abandon the auto return. Even if it was working, it's of marginal value. I don't think any current models have it. Parts are hard to come by and I get the impression it's not very robust.
2. Theoretically, you might be able to convert the swing valve section from solenoid to manual. But determining what Husco parts are required would be time-consuming, and not cheap. Then you'd have to come up with the linkage parts to convert that joystick to resemble the other one.
3. I would replace the entire valve. A monoblock valve like this to replace the existing sectional valve can be had for $500-800. (I think the two center handles can be reversed to face the other direction.)


I'd try to find a 7 spool valve while you're at it. This would furnish control for a future hydraulic thumb. Notice the third center handle in the picture below.

There are several considerations
• Although this implementation doesn't require it, I'd try to get a power beyond adapter with the valve. In the future, you could run a tank line from the bh to the tractor sump.
• Control lever orientation - ideal valve mounting orientation would be like the existing. You'd need to make sure the controls are accessible from the operator position.
• The original joystick linkage would be discarded if a valve with its own linkage, like on the valves pictured above, is used.
• Installation would include new mounting holes, probably new holes to accommodate the controls, and probably new fittings to adapt from the new valve to the existing hoses.

@TheOldHokie could add to this conversation for sure.

 

[Ken speirs]

Wow, this is incredibly helpful and clear, and still I am freakin intimidated to do it, not having any experience working on tractors. But one must forge ahead.

 

[PoTreeBoy]

Wow, this is incredibly helpful and clear, and still I am freakin intimidated to do it, not having any experience working on tractors. But one must forge ahead.

OK, you have your tractor issue fixed I see, so onward with the hoe. I have conversed with the expert and he mostly agrees with the way I have you going.

He prefers a separate electric valve if you ever want a hydraulic thumb. If you get a thumb, you want hydraulic, not manual. Reminds me that I finally decided to go electric if I ever add a thumb. But that's partly because I'd have to add a section to my Husco valve and cobble up the linkage. It's your call whether to get a 6 or 7 spool valve. If only $100-150 more, I'd get the 7. You don't have to use it, but you'd have it.

Moving on, a few pointers
• Cleanliness is important; a little dirt can cause untold grief. Clean and degrease that area before opening the system. Plug or tape any open fittings to exclude dirt, water, etc.
• Label or mark any hose you remove and the port you remove it from. Crossing connections can also cause misery. I've used an engraver, marker punches, and colored wire ties. Do not rely on permanent markers; hydraulic fluid removes it.
• I think you indicated you have the WSM for the B20; is the backhoe included? Please post the hydraulic diagram in the backhoe section. Here's the L35's:


Also, I think there will be a control valve image, similar to this, please post:

You'll notice those valves and ports are labeled. This will be useful later. Print out the valve layout so you can write down the colors or markings you use as you disconnect hoses.
• Remember to take pictures as we go along. Could you post a picture of the valve similar to the first one you posted but more directly head-on?
• Looks like you have some body work to do on the pedestal; I'm not going to address that. Do you have the top?
• Budget - you should be able to buy a valve for ~$500 and I'd budget maybe $300 for other stuff, mainly hydraulic fittings on the valve. If you select a valve with the same orientation as the existing, you can reuse the hoses, at least all but maybe two. There are cheap valves out there; one of the pictures I posted above from eBay has one for <$200. But the title and the picture don't agree so there is some risk.
• Tools, etc. - You'll obviously need wrenches to fit the hose nuts and fittings, and to remove the mounting bolts and nuts. Be prepared to drill new holes for mounting and to accommodate the levers. You may want to bend the levers later to fit your taste.

If this is agreeable, post those figures and pictures and we'll proceed.