Hydraulic arms not moving?

[kubotanewbie]

Greetings - my first post here.

My tractor is an older model of Kubota (8200HST) with loader & backhoe.

I'm preparing to temporarily replace the backhoe with few other attachments I ordered and I'm not quite clear on the rear hydraulics.

The hydraulic arms (in the attached photo) don't seem to be moving when I move the "hydraulic control lever" located to the right of the seat.

I'm not sure the back end of this tractor was ever used for anything other than the backhoe (which works fine), but I have the lifting rod & lower links for it, so I figured everything should work.

Are things magically going to start working once I remove the backhoe and attached a plow for example or is there something I need to change first?

I'd expect that by moving the hydraulics control lever located next to the seat I could observe the hydraulics arms move up & down.

Am I missing something obvious?

Thank you!

 

[irvingj]

Yep, I'm a newbie, too, but here are some thoughts:

Well, it looks like the 3PH arms are in the down position.... Does the hydraulic system make any noise when you attempt to raise them? If they're "frozen" you should probably hear some squealing as the system attempts to lift, I'd think.

Failing that, I know you can "lock" the arms in the up position... but is the lock on the floor (probably a knob) screwed all the way in to the lock position? Don't know if that would interfere with raising or not, but possibly.

And, yes, at least on my tractor, IIRC, I think the hose connections to the backhoe need to be removed & reconnected (with a return line) so the 3PH will operate. This sounds most likely. Hard to remember now; I leave the BH on all winter for ballast when snowblowing, and the only time I use the 3PH is to control the mid-mount mower deck-- with the BH off. I'm just not remembering if the 3PH and BH are mutually exclusive....

No manual? They're great to have around; perhaps you could get one from the big K. Hope this helps!

 

[kenstrac]

Disconnecting the backhoe will have no effect on tractor hyd. since the backhoe has it's own pump.
does the tractor have a loader and if so is that working?

 

[anojones]

One of the hydraulic experts will chime in, but doesn't a backhoe need a "power beyond" which bypasses the 3 point hydraulics- thus unhooking the backhoe will allow for the 3 point to work.

 

[kenstrac]

One of the hydraulic experts will chime in, but doesn't a backhoe need a "power beyond" which bypasses the 3 point hydraulics- thus unhooking the backhoe will allow for the 3 point to work.

Well thank you, I guess my observations that the backhoe is self contained and has nothing to do with the tractor hydraulics is mute and does not make me an expert. Maybe JJ can chime in and give the same answer since my skills ain't worth a rats *****

 

[MarEng]

There are two arrangements (that I've seen) for 3-pt backhoes. One uses the PTO to drive a separate pump mounted on the BH. The other (ours) uses the tractor's pump. When I remove the BH I take the pressure line to the BH and reconnect it to the 3-pt arms - look for a loose hose floating around back there with a quick connect on it that matches the end of your BH pressure hose. Once this is done the 3-pt begins working. The return line that connected to the BH now floats around collecting dirt and debris. I usually plastic bag and duct tape (the handy man's secret weapon) whichever end is floating around at the moment to try to keep it clean.

I did have a problem the first time I removed the BH (two years after purchase). No pressure/3-pt movement. I changed all of the filters. Nothing. Off to the shop. The hydraulic filter base was found to be plugged with trash. I suspect there was a leg of trash in the return line that blew out the first time it was connected and overwhelmed the filter. Took somebody with gages and some know how about 15 minutes to find it and another 15 minutes to pull the filter base and clean it.

 

[Kernopelli]

I agree with kenstrac, it appears your BH has a PTO pump so it uses a separate hydraulic system from the tractor so the BH should not make a difference. I am not familiar with your tractor whatsoever but I would first make certain that you are using the correct control valve and not a lever for something else like a draft control. Then I would check to make sure that all linkages are attached to the control valve as far as you can trace them. Check anything that may lock out the rockshaft ("hydraulic arms") function as was mentioned by irvingj. We are assuming that your pump is working (I don't know if your tractor uses a separate pump for the HST but suspect it might). Does the tractor have a front loader and if so does it work correctly?Do you have a manual? If so, this would be a good place to check for any hints as to what to look for. If all of these things work, it could be a relief valve that is stuck open or a piece of debris in the control valve. This makes things a little more complicated so start with the basics and let us know what you find.

 

[kenstrac]

I agree with kenstrac, it appears your BH has a PTO pump so it uses a separate hydraulic system from the tractor so the BH should not make a difference. I am not familiar with your tractor whatsoever but I would first make certain that you are using the correct control valve and not a lever for something else like a draft control. Then I would check to make sure that all linkages are attached to the control valve as far as you can trace them. Check anything that may lock out the rockshaft ("hydraulic arms") function as was mentioned by irvingj. We are assuming that your pump is working (I don't know if your tractor uses a separate pump for the HST but suspect it might). Does the tractor have a front loader and if so does it work correctly?Do you have a manual? If so, this would be a good place to check for any hints as to what to look for. If all of these things work, it could be a relief valve that is stuck open or a piece of debris in the control valve. This makes things a little more complicated so start with the basics and let us know what you find.

Thank you! I take it you looked at the photo and came to the same conclusion I did that it's a self contained backhoe.And the next thing is to find out if the loader works that would give some insight of what to trouble shoot next.

 

[Dead Horse]

If you have rear auxilary hydraulic connectors (with an actuator valve at the seat or some other location) such that the circuit is "open", your lift will not get pressure until you close the circuit.

 

[kubotanewbie]

Disconnecting the backhoe will have no effect on tractor hyd. since the backhoe has it's own pump.
does the tractor have a loader and if so is that working?

Yes, the tractor has a loader and that's working fine.

 

[kenstrac]

Does the loader have it's own pump does the tractor have PS?

 

[kubotanewbie]

Thanks all for trying to help a newbie. I appreciate the help.

Does the hydraulic system make any noise when you attempt to raise them?

No. No noise, no resistance I could feel on the lever either.

If you have rear auxilary hydraulic connectors (with an actuator valve at the seat or some other location) such that the circuit is "open", your lift will not get pressure until you close the circuit.

I'm not sure I understand what you're saying. I don't know if the answer here is yes or no, but I will try to describe the situation a bit better.

Disconnecting the backhoe will have no effect on tractor hyd. since the backhoe has it's own pump.

The backhoe indeed has its own pump, which is attached to the PTO with two hoses. One house goes to the backhoe filter, the other goes to the backhoe main valve.

When I operate the backhoe, I see the PTO shaft turning, which I assume is what generates the hydraulic pressure to lift and turn the bucket, but what do I know - I might mis-interpret things.

I included two more attachments that hopefully clarify the setup. One showing the backhoe (with the panel off, showing the hoses) and the other showing the main hydraulics pump feeding the front loader, which works fine) and showing the lines that go to the back - to the rear hydraulics.

I do have the manuals (for the tractor and for the backhoe). They describe the parts and the installation, but don't quite answer my question. I can scan the relevant pages and post here, if that would help.

Is it possible that once I disconnect the backhoe pump from the PTO, that the pressure will come back and I will be able to raise and lower my implements?

Can I just simply disconnect these hoses coming from the backhoe to the backhoe pump. As in - is this a safe thing to do with the tractor turned off or do I need to be worried about the pressure of the oil in those hoses?

 

[kenstrac]

Do any hoses from the backhoe go to the loader or tractor?

 

[jenkinsph]

If the backhoe is self contained with the pto pump (thats what I observed so far) I would remove it to get it out of the way. Then check the linkage from the rockshaft control lever to the rockshaft valve, make sure the linkage is hooked up, as the poster did say that there was no resistance in the lever. Could be the linkage was disconnected to prevent the arms from raising up and interfering or damaging the backhoe mounting. Just a thought.



kenstrack, you are right, reading the thread from the beginning and seeing the pto pump I was humored. Gotta look at the pictures!

 

[kenstrac]

Is this a directional control valve?

 

[Dead Horse]

Is this a directional control valve?

Sure looks like it.

Generally those twist valves have a 90 degree sweep and they are typically used to turn flow off for the loader when it is disconnected from the tractor.

My old heston has a valve at the back near the lift that is used to adjust "up" response as opposed to the one generally between your feet below the seat that adjusts "down" response.

On the up response valve, it is possible to have it cranked so low that the lift will not rise even without a load on it. If your tractor has one of these, this could be the issue. The fixture on this valve is a threaded cap with a slot in it for a LARGE screw driver. I use it to slow down the lift response for a light implement such that I can get smooth "up" motion as opposed to jerking motion. The trick is to tune the valve to the weight and functionality of the specific implement.


to clarify on the auxiliary HYD point I made earlier, the example I give is as follows: When I am running my splitter off the aux hyd ports at the back of my tractor, which are valved by a control lever at the seat, I bungee the lever in one direction or the other such that the valve on the splitter gets a constant flow. In order to lift the splitter with the TPH, the aux hyd valve has to be back in the neutral position or the lift will not get flow.

If I use the loader power beyond circuit, (I have both circuits plumber to the back of the tractor) this is not an issue. However once again only one circuit choice can be pressurized at a time.

 

[J_J]

Is this a directional control valve?

Definitely not a pump.

I believe this to be a selector/control valve, used to route hyd fluid to the front, rear, or both . I have something similar on my Kubota. Try turning the valve one way o the other. A gage would be a big help

 

[dboacres]

If your backhoe uses a PTO hydro pump, then it is like my neighbors Kubota. The 3 point mount for the backhoe will not allow movement of the tractors three point hydro arms. Actually is very hard on system to move 3 point lever with backhoe attached. Take backhoe off first.

 

[AchingBack]

If your backhoe uses a PTO hydro pump, then it is like my neighbors Kubota. The 3 point mount for the backhoe will not allow movement of the tractors three point hydro arms. Actually is very hard on system to move 3 point lever with backhoe attached. Take backhoe off first.

Correct. Remove backhoe, and connect loose male to loose female, and your 3PT should work.

 

[Leejohn]

Like it was said 2 or 3 times, this is a stand alone BH.
It should be a B4690B BH. This is from kubota's B series implements

2 point mounted with fixed top link. Self-contained hydraulic system powered by direct coupler PTO. Uses B21 (BT751) buckets. You must order bucket separately. Check ROPS application chart on previous page. B8200, B9200, B2150 require 70050-93213 bracket. Retail was $6929.00.

The 3 bolts that have no paint on them were added when the loader was put on. I would guess the BH at the same time. They disabled the 3pt and took all lift link and arms off... You trouble is in the hydraulic block. turn that bolt in. The one thing I don't understand is the loader valve seems to have a PB line feeding the 3 pt. IF so there might of been no reason to unscrew that bolt. That should be in the manual, but hard to understand sometimes.
The plug just above the dip stick is the relief valve and the long hex above the bolt that screws in and out is the flow divider.
I would do like was said. Get the BH off. There alots of guys on here that well help you to get the 3pt working.