Backhoe Pump Deadheaded???

[elkmtngear]

99% of pumps can only rotate one direction,,
rotating the pump the opposite direction will cause the pump to blow the seal at the input shaft,,
The pump can be an exact replacement, but speced for the wrong rotation,, and you have a problem.
Some pumps can have the rotation changed by the user,,, by flipping some part of the pump.

Also, if the inlet and outlet to the control valve are swapped at the time of connection, the pump will have no relief valve, and the seal at the pump will blow.

Having the correct pump (rotation) and having the correct fluid direction flow is critical,, do not guess,,,

Pretty sure that's what has happened, although I'm not sure how. Apparently I need to check the seal, and double check the pump direction.

 

[ericm979]

The overflowing pipe in pic #2 is on the tractor? Try running the tractor with pto on and at the engine speed that corresponds to 540 rpm at the pto, without putting the BH's pump on the pto. Maybe you ran the post hole digger at low rpms or not long enough to show the problem.

Overfilling the tractor's transmission could cause oil frothing which could make some oil come out the breather. But the pump on the pto shaft can't put pressure or oil into the transmission.

 

[elkmtngear]

The overflowing pipe in pic #2 is on the tractor? Try running the tractor with pto on and at the engine speed that corresponds to 540 rpm at the pto, without putting the BH's pump on the pto.

I'll pull the pump and try it. I always ran the posthole digger with the lever at the 540 position, and the tachometer in the "green".

 

[dfkrug]

I've wondered if the peculiar milkiness is due to the detergents in modern oil.

Yes, and the detergents and other additives seem to keep the water in suspension indefinitely. I drained 6 gallons out of the above Kubota B8200, and put it all into clear 1-gal jugs. After more than a month waiting for recycling, there is no oil/water separation.

What this means is the OP could have water in the oil for years, and not suffer from major deleterious effects due to separation.

For the B8200, I drained the sump, and added "SOUNDGUY's Elixer", a mix of isopropyl alcohol, ATF, and diesel. Then ran the tractor a while and drained that. After adding real THF, it will be drained again in maybe 10hr of use.

I also heated a small sample of the milky fluid to see if I could boil off the water. It worked, but a LOT of water was in there.

 

[oldnslo]

I ran a posthole digger off the regular PTO shaft, but this is the first time I've tried running this pump off the accessory pto

What is the difference between regular PTO & accessory PTO? How does the Back hoe pump connect to this accessory PTO? I could not tell for sure from the pictures but does not look like the pump shaft seal would leak oil into the tractor but i could be 100 % wrong.

Gear pump rotation: The oil travels around the outside of the gears so when spinning the input shaft oil will travel from inlet around outside of gear and then pushed out he outlet when the gear teeth mesh.

 

[BukitCase]

OldnSlo, check the PTO specs here
TractorData.com Jinma JM-554 tractor information

I'm thinking "accessory" might mean 1000 RPM? Usually, those have a separate shaft with more splines ... Steve

 

[rScotty]

Like I said, Tractor is never left out in the weather, and hasn't been run in the rain for that matter. I've been using the FEL and the posthole digger all Summer (and it's been a dry Summer). This symptom only occurred when I hooked up the PTO pump and backhoe.

That makes sense. From the first picture that you posted back on message #1 - and then looking at the direction that the hoses are going - I would guess that your PTO pump is getting its oil from a separate reservoir in the backhoe itself. That's common practice, and it makes the backhoe hydraulic fluic completely separate from the fluid in the tractor. No intermixing of fluids.

If that's the case, it wouldn't matter where the Tractor&FEL&PHD are kept. What matters is wherer the backhoe is kept....or rather where it has been kept since the last backhoe hydraulic fluid/filter change.

Looking at the 2nd photo, that circled part doesn't look stock to me. Does it only overflow when the PTO is operating? It sort of looks like a home-brew part attached to either the suction or pressure port on one of the tractor's internal oil pumps. I don't know the Jinma 554, but a diagram of the tractor's working parts should show that port. Tractors with powershift sometimes have an extra hydraulic pump in the transmission. But it is usually not related to the PTO and certainly not to the backhoe.

But if you look at dfkrug's photo in message #16 above.... on that B8200 he got.... now there's a tractor that was pretty obviously left outside without a cover. I agree that modern detergent oils are so good at capturing water that in trannys I've opened up, very little damage is done by the water/oil mixture while it just sits. It does need to be changed before running it of course.

BTW, those are some clever science experiments dfkrug ran on that water/oil emulsion. Simple stuff, but enough to point in a direction towards confirming what we'd suspected about emulsions. Thanks.
rScotty

 

[elkmtngear]

I will have to post more specific pics Tomorrow. The PTO pump fits on a small shaft up above the main PTO shaft (the large, splined shaft). I pulled the pump this evening, and clean hydraulic oil came running out around the small shaft on the tractor (flowed out for a good 10 minutes...at least a couple gallons). Backhoe sump is way down. So, it appears the pump was definitely driving fluid into the tractor.

 

[rScotty]

I will have to post more specific pics Tomorrow. The PTO pump fits on a small shaft up above the main PTO shaft (the large, splined shaft). I pulled the pump this evening, and clean hydraulic oil came running out around the small shaft on the tractor (flowed out for a good 10 minutes...at least a couple gallons). Backhoe sump is way down. So, it appears the pump was definitely driving fluid into the tractor.

Hmm....Two PTO shafts? One larger (diameter) than the other? That's a new one on me. But like others, I am not familiar with the Jinma.
On most domestic tractors the PTO-driven pump simply slides over the PTO splines and is kept in place with a short chain. How does your hydraulic pump mount?

If there are two shafts both parallel and close to one another I have to wonder if they are directly geared together. If so, the rotations would be opposite one another. As you have the pump off now, it may be possible to rotate the shafts with your fingers if the PTO clutch is disengaged.

I was just reading through some of the old 2008 posts here on TBN about the Jimna hydraulic system. It really is different. It sounds like it can be made to work, but the flow controls are not at all obvious. I hope you have access to good operator's manuals. I'm afraid my expertise in hydraulics doesn't extend to something designed in the Jimna manner.

If it were mine, I'd either want to get some good manuals and figure it out.... or just buy a standard 540 rpm USA type PTO pump and use the regular PTO.
Also read through those old threads on Jimna hydraulics.
rScotty

 

[BukitCase]

Uh, guys - if you follow the link I posted earlier and read a bit, apparently that tractor has THREE different PTO speeds; 540, 720 and 1000 RPM. I've seen others with 540 and 1000, 720 is new to me. The two speed versions I've seen typically have a finer splined shaft for the 1000rpm out, apparently used more in Europe than the US.

The literature on my Caroni flail mentions that option, but it doesn't seem to be offered on US versions... Steve

 

[elkmtngear]

How does your hydraulic pump mount?

Here's a re-oriented pic (labelled). The pump bolts to the tractor above the regular PTO shaft, and has a slotted adaptor that joins the shaft to the pump.



This is the type of interface on the back of the pump:



The PTO lever has 2 speeds (540 and 720). Posthole Digger was run at 540.



I'll go through the Jinma Threads, thanks for the tip!

 

[ericm979]

Could you show us where the pump fit on the tractor?

The usual PTO pumps have a hollow splined port where the typical 6 spline PTO stub fits. The pump is sealed as is the PTO stub on the tractor. There's no way oil from the pump can get in the tractor unless seals on both the pump and the PTO stub are totally missing and even then most of the oil would end up on the ground. Your pump looks very different. It may be special for jinma. This may be why people are confused, we all assumed you had the typical pump.

Typical PTO pump: 3.41 cu in 7.4 GPM 54 RPM Dynamic GP-PTO-A-3-6-S Hydraulic PTO Pump | Dynamic | Brands | www.surpluscenter.com

 

[elkmtngear]

Your pump looks very different. It may be special for jinma.[/url]

Yes, apparently it's unusual. I called Circle G Tractors, and they were not too surprised. Apparently I need to rebuild the pump, there are several seals in it that can fail. Ordering a rebuild kit.

 

[dfkrug]

The pump is sealed as is the PTO stub on the tractor. There's no way oil from the pump can get in the tractor unless seals on both the pump and the PTO stub are totally missing and even then most of the oil would end up on the ground. Your pump looks very different. It may be special for jinma. This may be why people are confused, we all assumed you had the typical pump.

That Jinma is indeed very unusual. Like you, I do not see how oil would get from the failed pump into the tractor sump. TWO seals would have to fail, I would think.

Note that Deere x55 tractors also put their implement pumps hanging off the back, right above the normal PTO shaft.

 

[oldnslo]

Elkmtn
Looking at the picture of the pump it is clockwise rotation as viewed looking at the tang on the drive shaft. Which way does the PTO spin on your tractor

I.e. while looking at rear of tractor where the pump mounts it would be counterclockwise

 

[elkmtngear]

elkmtn,
Where is the pump inlet hose connected for the back hoe pump? If connected to a reservoir on the back hoe then all of the lines on the back hoe should remain connected to the hoe. If one is the the hoe and the other to the tractor you will over fill one reservoir and drain the other.

If connected to the sump or reservoir on the tractor then the return or tank line from the back hoe must also be connected to the tractor sump preferably below oil level and as far away as possible from the pump inlet.

Returning oil above the oil level can cause foaming and aerate the oil.

Another potential problem is the back hoe pump flow rate vs the sump size of your tractor. To much flow rate can also cause aeration - foaming of the oil.

Both the inlet and outlet hoses are connected to the backhoe only. The backhoe tank was full to the dipstick mark when I started, but now is very low. I'm certain that oil was being pushed into the tractor through the shaft seal on the pump.

 

[elkmtngear]

Elkmtn
Looking at the picture of the pump it is clockwise rotation as viewed looking at the tang on the drive shaft. Which way does the PTO spin on your tractor

I.e. while looking at rear of tractor where the pump mounts it would be counterclockwise

I was told by the Circle G parts guy, that the upper tang shaft where the pump mounts, goes the opposite direction of the PTO shaft. The hydraulic pump was supposed to be designed for that, but who knows? I need to check it thoroughly after I kit it.

 

[rScotty]

Knowing which way the tang is turning will probably tell you which of the hoses is feed and which is pressure. You will confirm that when you kit it & actually see the internal gears. The way that the tang is off-center on the pump makes it a sure bet that you have a typical spur gear type hydraulic pump. So find the direction of rotation of the tang, then study this link and you will see how to tell which hose is your pressure hose to the BH controls and which is inlet supply. Note that the oil flows around the outside of the gears... carried by the space ibetween the gear teeth and case. Oil is NOT squeezed between the gear teeth to any great or effective amount..
Hydraulic Spur Gear Pump | Hydraulic Pump

I'm not surprised that the upper tang turns reverse of the PTO - all that means is that tang and PTO are geared together without an idler gear in between. That makes for less parts, easier to design, and enables the PTO clutch or actuation to work both systems.

It actually looks like a pretty good system. Nice machining, nice pump casing, decent bolt pattern. Is the rest of the tractor as good?
rScotty

 

[elkmtngear]

Knowing which way the tang is turning will probably tell you which of the hoses is feed and which is pressure. You will confirm that when you kit it & actually see the internal gears. The way that the tang is off-center on the pump makes it a sure bet that you have a typical spur gear type hydraulic pump. So find the direction of rotation of the tang, then study this link and you will see how to tell which hose is your pressure hose to the BH controls and which is inlet supply. Note that the oil flows around the outside of the gears... carried by the space ibetween the gear teeth and case. Oil is NOT squeezed between the gear teeth to any great or effective amount..
Hydraulic Spur Gear Pump | Hydraulic Pump

I'm not surprised that the upper tang turns reverse of the PTO - all that means is that tang and PTO are geared together without an idler gear in between. That makes for less parts, easier to design, and enables the PTO clutch or actuation to work both systems.

It actually looks like a pretty good system. Nice machining, nice pump casing, decent bolt pattern. Is the rest of the tractor as good?
rScotty

Great link, exactly what I needed. Thank You.


So far, the only problem I've had with the tractor, was a broken steering knuckle on the front, which I had to replace. The FEL is a beast, I've cleared a bunch of manzanita with it. I've been itching to get this backhoe working, so I could play around with it.