BH Hydraulics Available for use on B7800?

[hill]

What I mean is - when my backhoe is parked in the barn the feed and return lines for it are connected by QC's to form a loop and the ready-to-open line intrigues me as an easy source for TNT use or any other use by addition of spools and cylinders.

However, I know that some tractors derive their pressure for rear mount hydraulic accessories by bypassing and deactivating the hydraulic power to the 3-PT lift bars. I don't know if my Kubota does that and am hoping someone knows off the top of their head.

Without 3PT lift power it'd be impossible to use a TNT setup, obviously.

I do have the W.R. Long electro/hydraulic grapple power that added a valve under my bucket joystick and replaced the stick handle with one that incorporates a toggle switch to electrically activate the grapple. That's worked perfectly and if I remember right their valve does have a power beyond connection that I could use to run lines to the rear. It'd be a lot more complex and hydraulic routings always get me all confused when I start thinking about adding something.

When I look at that loop for the dismounted backhoe it seems like such a waste if I don't put it to work somehow.

 

[magicheater]

In my experience you can plug something else in. It is basically a series circuit, with first in line getting served first. I have a joystick after the loader valve followed by the back hoe option you speak of followed by a selector valve for front/original remote functions.

 

[hill]

In my experience you can plug something else in. It is basically a series circuit, with first in line getting served first. I have a joystick after the loader valve followed by the back hoe option you speak of followed by a selector valve for front/original remote functions.

Good! That's what it looks like but I'd have to be sure before starting to unbolt stuff.

The thread that mentioned a tractor usinghthe 3PT power to operate a BH WHEN the BH is mounted is this one:

http://www.tractorbynet.com/forums/owning-operating/212650-110-tractor-loader-backhoe-3-a.html

Whatever a "110 TLB" is seems to switch the hydraulics around according to what is mounted up. I'd never heard of such things before that.

 

[magicheater]

Good! That's what it looks like but I'd have to be sure before starting to unbolt stuff.

The thread that mentioned a tractor usinghthe 3PT power to operate a BH WHEN the BH is mounted is this one:

http://www.tractorbynet.com/forums/owning-operating/212650-110-tractor-loader-backhoe-3-a.html

Whatever a "110 TLB" is seems to switch the hydraulics around according to what is mounted up. I'd never heard of such things before that.

I would check your owners manual before doing any mods. A"110 TLB" sounds like a John Deere and could be different. I have 2 Kubotas, L4350 and B7800 and find them to be the same regarding hydraulics.

 

[hill]

Yeah, that was about a JD model. Don't know why I didn't recognize it.

Now if someone has figured a way to hydraulically slide a brushhog from centered on tractor to three or four feet over toward either side and still be able to cut I'll be a happy man.

 

[Ductape]

Though it is certainly possible to rig up a set of valves for your T n T with quick connects ........ why not just plumb them permanently without using the quick connects for the backhoe? Purchase a valve with PB and plumb it so that the current backhoe 'in' line goes to the new valve. 'Power beyond' on the new valve goes back to the backhoe quick connects, and the 'out' on the new valve goes to the sump. The return to the sump is the only line you can 'tee'. Just remember all valves connect in series.

 

[J_J]

Ductape

'Power beyond' on the new valve goes back to the backhoe quick connects, and the 'out' on the new valve goes to the sump. The return to the sump is the only line you can 'tee'. Just remember all valves connect in series.


If he does add the new valve, and removes the BH. he will still have to make a loop for the flow from the new valve PB to the 3pt.

Now, if he added a detent valve, with PB, and fed it to the 3pt, then he would use the work ports to feed the BH, and if he removed the BH, no problem. The valve is still in series with no bypass hose necessary.

That loop thing is not exactly a good thing because that hose connects the flow in a series circuit, and if it has QD's in them, and one of them is disconnected with the pump running, you have deadheaded the hyd system.

If the PRV can't handle it, could still burst the pump, or hose.

 

[J_J]

hill,

If you have the Long kit, you are already using the PB outlet to pass fluid to the back for the 3pt/BH.

 

[hill]

hill,

If you have the Long kit, you are already using the PB outlet to pass fluid to the back for the 3pt/BH.

Yeah, the W.R. Long kit rerouted the PB of the loader valve to the Long input to pressurize for the grapple. Then the W.R. Long PB port is plumbed to the BH pressure input. That circuit appears to be independent - large hose directly to the mounted BH valve with no connection to the 3PT which is what I came to verify and am pretty sure of now.

The 3PT appears to be valved and controlled internally by a combined control and relief valve bolted to the underside of the cylinder housing. It does not look like the BH circuit has anything to do with the 3PT supply or dumpoff and is an unused loop back to the W.R. Long valve when BH is off tractor.

The BH circuit, when the backhoe is dismounted, is connected to itself - one side came with a male and the other a female QC with normal procedure being a disconnect from the BH valve of both hoses, and then connecting the two loose ends together to form the loop back to the (now) W.R. Long valve.

"That loop thing is not exactly a good thing because that hose connects the flow in a series circuit, and if it has QD's in them, and one of them is disconnected with the pump running, you have deadheaded the hyd system"

Yep, I've looked at that OEM QC loop connection since the first time I dismounted the BH. It's pretty well protected inward of the bottom of the ROPS and aside the transaxle, but I keep it safetywired just in case Murphy comes by. If it came loose I'd have a pretty fast loss of fluid, possibly before I knew what was happening. I try to keep my eye on it, especially when brushhogging.