How to switch boom for stick control

[derekp69]

I bought a used BH77 and the controls are "cat" vs "John deer" as I'm told. I need to switch so left control stick operates swing and boom and right control stick operates curl and stick. I think it's 2nd valves from outside but can't find any help/confirmation. Thanks in advance.

 

[BAP]

I bought a used BH77 and the controls are "cat" vs "John deer" as I'm told. I need to switch so left control stick operates swing and boom and right control stick operates curl and stick. I think it's 2nd valves from outside but can't find any help/confirmation. Thanks in advance.

Someone must have swapped it already because the Kubota backhoe uses the same pattern as JD and Case. They probably changed the hoses on the valves themselves. You are most likely going to have to trace hoses and see where each one goes, then swap them around.

 

[TheOldHokie]

I bought a used BH77 and the controls are "cat" vs "John deer" as I'm told. I need to switch so left control stick operates swing and boom and right control stick operates curl and stick. I think it's 2nd valves from outside but can't find any help/confirmation. Thanks in advance.

The WSM should have that info. One word of caution. Both those valves have port reliefs and the relief cartridges msy need to be swapped as well as the the hoses. That info is also in the WSM.

Dan

 

[GreensvilleJay]

Please, BEFORE you make the changes, BUY a pack of rainbow coloured tyraps !!! Put TWO of same colour on every hose, then take 2-3 pictures. CONFIRM pictures show each hose has a different colour.
NOW proceed with the hose swap........

 

[TheOldHokie]

I bought a used BH77 and the controls are "cat" vs "John deer" as I'm told. I need to switch so left control stick operates swing and boom and right control stick operates curl and stick. I think it's 2nd valves from outside but can't find any help/confirmation. Thanks in advance.

Followup to my previous post. Heres the parts breakdown from Kubota online parts. Boom is valve D and dipper is valve B. The port reliefs are different which may explain the different part numbers but swapping the entire valve assembly along with the hoses would avoid the guess work.

Dan

https://shop.kubotausa.com/oemparts/a/kub/6091af7d87a86614f81c3fbe/b21000-control-valve-component-parts?lid=6076dfa14f231b5030d5ac9d

 

[PoTreeBoy]

I bought a used BH77 and the controls are "cat" vs "John deer" as I'm told. I need to switch so left control stick operates swing and boom and right control stick operates curl and stick. I think it's 2nd valves from outside but can't find any help/confirmation. Thanks in advance.

What you describe is the standard Kubota setup, someone must have changed it

There are assembly and WorkShop Manuals for the BH77 available at KubotaBooks. That should walk you through the changeover. No Operator Manual, but there is one for the BH75, which will be very similar.

 

[torch]

Followup to my previous post. Heres the parts breakdown from Kubota online parts. Boom is valve D and dipper is valve B. The port reliefs are different which may explain the different part numbers but swapping the entire valve assembly along with the hoses would avoid the guess work.

Dan

https://shop.kubotausa.com/oemparts/a/kub/6091af7d87a86614f81c3fbe/b21000-control-valve-component-parts?lid=6076dfa14f231b5030d5ac9d

My fear would be that whoever swapped things originally didn't know about the role of port reliefs and just swapped the hoses.


(PS: when I tried to follow your link access was blocked by cloudflare for some reason. )

 

[GreensvilleJay]

I'm blocked too, probably cause I'm in Canada,eh !

 

[TheOldHokie]

My fear would be that whoever swapped things originally didn't know about the role of port reliefs and just swapped the hoses.


(PS: when I tried to follow your link access was blocked by cloudflare for some reason. )

Yes, if its been altered time to check the numbers on the port reliefs to see what was or was not swapped.

Here is a link to Messicks

Kubota BH77 (7.7 FT BACKHOE) Parts Diagrams

Kubota Parts Catalog Lookup. Buy Kubota Parts Online & Save!

messicks.com

 

[torch]

Looking at the Canadian Kubota parts site, it appears there are two different port reliefs installed in the various outlets: "Port relief high" and "Port relief low". I assume high and low are relative to pressure.

From there it gets confusing as hell. There are 3 different relevant diagrams. Control Valve shows 6 different valve bodies, labelled A through E. Note the absence of an F. This is because there are two labelled C (apparently these are the outriggers and don't have port reliefs).

The Control Valve diagram labels all the ports A through G across the top and H through N across the bottom. But the Hydraulic Hose (Boom/Dipper) diagram relabels the ports such that B is now A, I is now B, E is now C and L is now D.

Near as I can tell, Dipper is the second third set of ports from the right (second valve body from the right, first two ports are Pump and Tank), boom is second set of ports from the left.

The Dipper valve body has one of each relief valve, with low on the top, high on the bottom. The Boom valve body has a high on both top and bottom.

If I've traced all that mess out correctly (which is by no means certain), mixing and matching would result in poor downward digging boom force due to lower available pressure.

The other thought that comes to mind is the Boom function should have a float position, IIRC. If the boom still has a float position in the current configuration that suggests the PO swapped the entire valve bodies, not just hoses and/or relief valves. That should be a simple check: which stick has the float detent now?

 

[TheOldHokie]

Looking at the Canadian Kubota parts site, it appears there are two different port reliefs installed in the various outlets: "Port relief high" and "Port relief low". I assume high and low are relative to pressure.

From there it gets confusing as hell. There are 3 different relevant diagrams. Control Valve shows 6 different valve bodies, labelled A through E. Note the absence of an F. This is because there are two labelled C.

The Control Valve diagram labels all the ports A through G across the top and H through N across the bottom. But the Hydraulic Hose (Boom/Dipper) diagram relabels the ports such that B is now A, I is now B, E is now C and L is now D.

Near as I can tell, Dipper is the second set of ports from the right, boom is second set of ports from the left.

The Dipper valve body has one of each relief valve, with low on the top, high on the bottom. The Boom valve body has a high on both top and bottom.

If I've traced all that mess out correctly (which is by no means certain), mixing and matching would result in poor downward digging boom force due to lower available pressure.

The other thought that comes to mind is the Boom function should have a float position, IIRC. If the boom still has a float position in the current configuration that suggests the PO swapped the entire valve bodies, not just hoses and/or relief valves. That should be a simple check: which stick has the float detent now?

I did not even try to follow your specifics but that is the nature of swapping things willy nilly.

Since someone of unknown skills and knowledge has played with it already I would disassemble the stack and reassemble individual valves in desired order checking relief cartridges to make sure they match the function.

Not a job I would welcome.

Dan

PS> Rereading the oruginal post its not clear anything has actually been swapped:

"I bought a used BH77 and the controls are "cat" vs "John deer" as I'm told.*

 

[torch]

Oooh, good point. There are even authoritative looking websites that have it backwards. EG:
https://speceps.com/blog/cat-vs-john-deere-controls-difference-comparison.html which claims JD follows the ISO pattern and Cat follows the SAE pattern.

So, Step 1: verify operation. <lol> Are they really switched, and if so, which one has the float detent?

 

[torch]

Ooops. Deleted duplicate post.