B8200 strange set up

torch

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Torch, honestly I can***8217;t remember as it happened so fast but the pop may have occurred right as I first activated the spool valve.
Sorry, which spool valve? The one controlling the 3ph or one of the FEL control valves?

If you look back towards the beginning of this post, you will see that goofy banjo connection at the 3 point connection that used to send pressure into my loader spool valve, along with a power beyond connection.
That may be the key clue here. If someone went to all the trouble of making their own home-made banjo bolt, then what else might they have done to McGyver this little Frankenstein?

Here's the thing: Kubota's "open centre" design requires that the 3ph spool valve dumps the fluid flow back into the reservoir whenever it is in neutral. That prevents any meaningful pressure rise ANYWHERE else in the system while the 3ph spool valve is in neutral. If one simply taps into the "high pressure" line to supply fluid to the FEL spool valves, one will never get any pressure in the FEL hydraulics.

The ONLY way to get pressure in the FEL hydraulics is to interrupt the flow to the 3ph spool valve. That's what the direction control valve in the hydraulic block does -- it closes off a passage between the FEL supply port and the PB port, forcing fluid to the FEL control. The FEL spool valves direct that fluid back to the 3ph circuit if and only if they are both in neutral.

Opening the direction control valve opens a passage that bypasses the FEL completely. It's purpose is to supply fluid to the 3ph on tractors that have no FEL. If one was to close it with the FEL ports plugged off, the system would be deadheaded at the hydraulic control block, causing pressure to rise until something blew.

So, I believe that someone must have reworked things at the 3ph end to perform the function of a closed direction control valve. I don't have a B8200. I have never worked on a B8200. I don't have the FSM for a B8200. This is all a thought excercise for me. But looking at the hydraulic piping parts diagram:



I don't see this unpainted mystery fitting on the diagram:



1: if that mystery fitting was removed, would the banjo bolt you bought secure the original painted line to the casting?

2: Is the home-made banjo bolt hollow all the way through?

3: If so, is the mystery fitting?

I strongly suspect that mystery fitting and/or home-made banjo bolt block off flow to the 3ph spool valve, and was the means that McGyver forced fluid to the FEL and back. I think -- in my long winded way -- this is what Wolfman was driving at, in his much more succinct way.
 
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Bigearl

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Dec 6, 2018
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Torch, I really appreciate all the feedback.

See the first picture. This was before I touched the tractor.

Yes the banjo bolt is hollow all the way through including the head of the bolt. The banjo bolt had double orifices, hence the two fittings. I say had, because it is now broken.

On the far right of the connection was a male orb fitting that had a 90 degree with a female swivel. This was my pressure in line to the spool valve block up in the cab.

The mystery fitting was connected to the pb line at the loader spool valve in the cab.

My tank line was tapped into the drain hole of the mid pto.

Lastly, my plan was to remove the mystery fitting, and use the correct bolt. So I removed the mystery fitting, installed new o rings and slid new banjo bolt thru, only for it to be too short! See second picture.

That’s when I decided to re use goofy banjo bolt and I plugged off the two fittings.
 

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Bigearl

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Torch, Wolfman

I have a feeling the home made banjo bolt was not suitable for the actual working pressure of the system after I plugged it’s previous path of least resistance. I don’t think I dead headed the pump. Check out my photos.

Wall thickness of new banjo bolt that is too short, roughly .135 inches thick.

Wall thickness of home made banjo, roughly .075 inches minus approximately .030 inches because it was internally threaded. Leaving roughly 0.045 inches of wall.

So the correct banjo bolt has nearly three times the wall thickness.

I also measured my hydraulic piping banjo connection, I’m wondering if this may be from a different model? If kubota says I have the right bolt, which isn’t long enough, then maybe my piping was switched out. I want to see if they can provide specs on the banjo fitting of a replacement pipe.
 

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North Idaho Wolfman

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Does this help clarify what the aftermarket banjo bolts and fittings were doing, and how capping the ends caused it to deadhead?



It looks like the main delivery pipe might have been changed from the original line, if you would take a picture of the connection point at the front of that line.
 

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torch

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I don't dispute that the bolt was a bit thin, however the pressure on that fitting should have been 0 psi with all spool valves in neutral!

If that homemade bolt was solid between the two cross-bores, then it would all make sense -- pressure from the pump hit the plug you installed in the end of the home-made bolt, deadheaded, and blew out the weak bolt.

But you say the bolt was bored through completely from end to end. Which, from your description of the original plumbing, would mean that the supply was directly tied into the PB port. I'm trying to wrap my head around how that could possibly work.

The only two scenarios I can come up with are:

1. There was a press-fit slug in the bolt between the two cross passages, which got blown into the 3ph spool valve when the bolt blew. Doesn't seem likely.

2. The return line from the 3ph spool valve to the reservoir was deliberately plugged off. Possibly by replacing one of the 021 bango bolts with a home-made solid version. In that scenario, the FEL relief valve would have been providing the return path to the reservoir through that goofy hose into the drain plug fitting. In other words, the whole system would have been under pressure at all times, like a closed-center system. But then the 3ph would have been inoperative.
 

torch

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Just to confirm I am envisioning this home-made bolt correctly, it is fully bored lengthwise and then cross-drilled in two places so that the 3 lines and the 3ph spool valve are all interconnected with no obstructions, like so?:

 

North Idaho Wolfman

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Just to confirm I am envisioning this home-made bolt correctly, it is fully bored lengthwise and then cross-drilled in two places so that the 3 lines and the 3ph spool valve are all interconnected with no obstructions, like so?:

If it was made like that it wouldn't have worked, there would have been no flow to the valve.
I'm pretty sure the bolt passed fluid on the outside from original to add on port and then flowed back in on the end. ;)
 

torch

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If it was made like that it wouldn't have worked, there would have been no flow to the valve.
I agree, it doesn't make any sense. But that seems to be what he is describing and the pictures seem to show it broke at a cross-drilled passage. If that's how the bolt was made then there's got to be something else going on that we don't know about.

If there's no cross-drilled passages, then your sketch makes sense.
 

torch

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This is the line that sounds like it was cross-drilled for both lines:
Yes the banjo bolt is hollow all the way through including the head of the bolt. The banjo bolt had double orifices, hence the two fittings. I say had, because it is now broken.
Next paragraphs throw another monkey wrench into the theories:
On the far right of the connection was a male orb fitting that had a 90 degree with a female swivel. This was my pressure in line to the spool valve block up in the cab.

The mystery fitting was connected to the pb line at the loader spool valve in the cab.
If the bolt was hollow, but not cross-drilled, so as to pass fluid from the factory line to the mystery fitting then those two lines are reversed. The mystery fitting should supply pressure to the controls in the cab and the PB should come back to the end of the bolt.
 

Bigearl

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Ok torch and wolfman, I owe you guys a beer.

I messed up big, and I did deadhead the pump. I removed the damage last night, and I discovered the goody banjo bolt was not fully hollow! I was so sure but I guess I never fully examined it. I’m an idiot!!! It all makes sense now, fluid went from pump to block, up to spool valve, power beyond brought it back to block, then it traveled back the blue line and pop, it had nowhere to go. I now fully understand dead heading. So the original setup makes sense also, flow to the spool valve was supplied by the blue line, sent out the side of the banjo bolt up to the spool valve, and power beyond brought it back to the mystery fitting.

Again, the home made banjo bolt was not fully hollow.

So first big question, is my pump ok? After I heard the pop I would say it ran another 10-15 seconds then I shut it down.

Back to the repair. I need either a longer factory banjo bolt to properly connect my piping, or maybe my piping needs to swapped out with a piece that has thinner banjo fittings? My piece looks original but who knows.

I’ve attached some photos, notice the difference in lengths of the bolting.
 

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torch

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I messed up big, and I did deadhead the pump. I removed the damage last night, and I discovered the goody banjo bolt was not fully hollow!
Great news, I'm glad that the mystery is solved. Don't beat yourself up over making a mistake -- the man who doesn't make mistakes is either lying or dead. And if he's dead, there's a strong possibility it was due to making a mistake! :p


So first big question, is my pump ok? After I heard the pop I would say it ran another 10-15 seconds then I shut it down.
Odds are the pump is fine. That's what I was referring to much earlier in this thread. The home-made banjo bolt probably acted like a safety valve and blew before anything else was damaged. A chain is only as strong as it's weakest link and all that. I wouldn't look for a replacement pump unless that one is proven damaged. (If it is, and IF you have a gear drive pump, then contact me -- I can give you a good deal on a new, unused replacement that I bought by, err, well, mistake!)

It is possible that Kubota put the wrong bolt in the package. I would take it back to your dealer's parts department with that pipe in hand and make it their problem. I doubt very much that the pipe was replaced with one from another tractor.
 

Bigearl

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Update for you guys. So Kubota is still saying that I have the correct replacement bolt, and they are also saying that the replacement supply piping is no longer an available item. So I look on ebay and see that a guy is selling the 3 point control valve and it has the banjo bolts to go with it. I reach out to this guy and he says he's got three B8200's that are parted. He claims he will be going to his storage facility this weekend, and he's going to confirm measurements on the bolt, and then sell me an OEM banjo bolt. I am really hoping this pans out because my only other real option is to have a machine shop make me a banjo bolt. I did talk to a hydraulic guy about rebuilding the loader spool valve, he said about 100-150 depending on what it is, but I'm still not sure if I'm going to do this. If it dripped occasionally that would be fine, the thing I don't want is another catastrophic failure resulting in 5 gallons of fluid on the floor or even worse, an injury of some sort.

Can anyone by chance identify my spool valve? See photo
 

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Bigearl

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Well I got my eBay special banjo bolt today. Oem bolt and it’s the correct length. I went ahead and installed the supply piping, so it’s back to original design and the goody two holed banjo bolt is out of the picture. Tomorrow I’ll pick up another 5 gallons of hydraulic fluid after my brand new fluid got trashed.

I’m a little nervous but I think it’s all going to work out now. I’ll be prepared at start up with drain pans and I’m not going to touch the spool levers until I verify no leaks.

I never did get any opinions as to having the loader spool valve inspected or rebuilt. It’s oily and slimy but I’m gonna see what happens. I’m thinking when the pump dead headed that there was a pressure surge and caused some leakage. Any last thoughts on loader spool valve???
 

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torch

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I'd hold off on the spool valves for the moment. Maybe clean them off so you can see any fresh leakage.

A suggestion: Don't start the engine right away. Crank it over with the starter, but leave the fuel lever pulled back so the engine won't start. If something is still dead-headed, I think the starter will quickly slow down and you will have time to release the key before damage is done.

Even better might be to loosen the banjo bolt on the return line at the reservoir and make sure oil is flowing all the way through the system while the starter is cranking it over.

I'm pretty confident that all is OK now, but, you know, just in case... ;)
 

North Idaho Wolfman

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Ditto on what torch said.

If the spool valve is leaking your most likely way better off just replacing it with a newer version.
 

Bigearl

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Thanks torch for the advice. So today I got roughly 5 more gallons of udt. I filled the tractor and it seems to be full by only adding about 3 gallons of fluid so not all fluid was lost. I did crack the rear banjo open and cranked it over good three times. I never did see fluid coming out but I also never heard any dips in the starter.

I fired it up, I heard no pops or weird noises, and there was nothing leaking! I gave it some more fuel and pulled it out of the garage. I’ve learned that the theee point doesn’t like to drop unless I’m at an idle. Keep in mind there is nothing attached to the three point. Aside from that the three point seems to operate like it should. I haven’t messed with that knob by the seat maybe that is something to explore.

Now into the front blade and spool valve. The cylinder that controls the up and down has two hydraulic connections meaning an in and a out. This function works great up and down and I even tested the float which seems to work as well. Now the left or right cylinders only have single hydraulic connections. I can operate the left cylinder which turns the blade to the right, but the right cylinder will not move.

I tried reversing my connections thanks to the quick connects, when I did this the blade twitched but would not move in either direction. So lastly I moved my hoses over to the other lever and they worked perfect left to right. So the problem is my spool valve.

I remember this clearly during the broken banjo event as the blade would not move to the left (right cylinder).

If I understand single port hydraulic rams, when one cylinder is pushing it causes the other cylinder to collapse. So my lever must be at least partially working. And when I try to move the blade to the left you can hear the load on the engine but nothing moves.

Prior to replacing my hoses the blade moved left to right with no issues. Did the dead heading do something to damage this spool valve? Do I have a block somewhere? Today was a good day as the banjo bolt thing is now resolved, but now i have this new issue.

Oh and looking at the bottom side of the spool valve tonight after I cleaned it up. There is no evidence of leakage and it’s dry.
 

North Idaho Wolfman

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I tried reversing my connections thanks to the quick connects, when I did this the blade twitched but would not move in either direction. So lastly I moved my hoses over to the other lever and they worked perfect left to right. So the problem is my spool valve.

I remember this clearly during the broken banjo event as the blade would not move to the left (right cylinder).

If I understand single port hydraulic rams, when one cylinder is pushing it causes the other cylinder to collapse. So my lever must be at least partially working. And when I try to move the blade to the left you can hear the load on the engine but nothing moves.

Prior to replacing my hoses the blade moved left to right with no issues. Did the dead heading do something to damage this spool valve? Do I have a block somewhere? Today was a good day as the banjo bolt thing is now resolved, but now i have this new issue.

Oh and looking at the bottom side of the spool valve tonight after I cleaned it up. There is no evidence of leakage and it’s dry.
You have a clogged, broken, or bad quick disconnect, it could be on the male or the female side. ;)
 

Bigearl

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Wolfman, you were right. Initially my left cylinder would push, right did nothing. I then removed the entire quick connect for the left cylinder. Now my right cylinder would move and nothing from the left. I then swapped out the female side of the quick connects and same thing.

I said f it, I took off the other quick connect so both my left and right lines went right into spool port. Wam it works perfect.

The only thing I didn’t try was swapping that one male side quick connect fitting, but remember at one time I tried these male ends on the other spool and both my cylinders worked.

One thing I found interesting is one of the quick connects is very snug with no play. The other one has a bit of play.

The two quick connects that are on the up down cylinder also have play and work correctly.

Aside from a couple quick connects I may not use, a banjo bolt from kubota that is too short, and a bunch of wasted fluid, i think this project is complete and i have a fully functioning tractor. Now if it would just snow!

Oh and remember the eBay oem banjo bolt, I paid 95 dollars for it! But he did pull it from a complete 3 point assembly.

Thanks guys for all your help.
 

torch

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I'm very pleased to hear that everything is working well now. I'm still trying to find my dentures under the desk after hearing the price of that banjo bolt though! :eek:
 

North Idaho Wolfman

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Aside from a couple quick connects I may not use, a banjo bolt from kubota that is too short, and a bunch of wasted fluid, i think this project is complete and i have a fully functioning tractor. Now if it would just snow!

Oh and remember the eBay oem banjo bolt, I paid 95 dollars for it! But he did pull it from a complete 3 point assembly.

Thanks guys for all your help.
Yes excellent to hear, and glad we could help!


I'm still trying to find my dentures under the desk after hearing the price of that banjo bolt though! :eek:
I did the same thing...but the wolves grabbed them and went and buried them in the snow! :eek: