Backhoe Pump Deadheaded???

[elkmtngear]

Rookie operator here. Checked the direction of flow on LW6 backhoe's pump before hooking up to my Jinma 554, by putting a clear tubing filled with fluid, on the outlet ports of the pump. Had to cross the lines to hook up correctly (suction side = large hose). See Image #1

After pressurization, hydraulic fluid is flowing (rapidly) out of the circled area in Image #2 (could someone tell me what this pipe's name and function is)? I'm assuming it's some sort of overflow valve.

Valve under the seat is completely screwed down tight. Tractor never had this leak, until I hooked up the hoe.


Wondering how I would locate a new seal for this pump, and if that would solve the problem? Thanks in advance.

 

[dfkrug]

First, I admit I have never worked on a Chinese tractor or backhoe attachment.

It looks like your hoe is using a PTO pump, according to your first photo. Your second shows a pipe connected to what looks like your tractor's sump. The 2 systems' hydraulics should be independent. If you connect your hoe backwards, and run it, you can blow a seal in the hoe valve.

That said, it looks like the pipe in your 2nd photo is some kind of tank vent, as you said. But it uses a hi-pressure hardline and banjo fitting. Strange.

 

[elkmtngear]

You're correct dfkrug, it's a pto pump on the rear of the tractor. Since they are supposed to be independent (the pto pump is supposed to use the backhoe sump)...I'm assuming that the seal on the pto pump must have blown, and is pressurizing the tractor sump?

 

[dfkrug]

You're correct dfkrug, it's a pto pump on the rear of the tractor. Since they are supposed to be independent (the pto pump is supposed to use the backhoe sump)...I'm assuming that the seal on the pto pump must have blown, and is pressurizing the tractor sump?

But they are not connected hydraulically at all.

Is the oil coming out the vent foamy or milky?

 

[elkmtngear]

But they are not connected hydraulically at all.

Is the oil coming out the vent foamy or milky?

I would say definitely "milky".

 

[rScotty]

by putting a clear tubing filled with fluid, on the outlet ports of the pump.
View attachment 616905

I'm wondering where you found a clear tubing that would stand up to hydraulic fluid and output pressure?

 

[elkmtngear]

by putting a clear tubing filled with fluid, on the outlet ports of the pump.
View attachment 616905

I'm wondering where you found a clear tubing that would stand up to hydraulic fluid and output pressure?

It was like clear PVC (very stout)...I just looped it between the ports, and used radiator hose clamps.

 

[rScotty]

It was like clear PVC (very stout)...I just looped it between the ports, and used radiator hose clamps.

You be careful. I doubt it is stout enough. Most PVC clear tubing is rated at a few hundred pounds pressure at most..and the rating goes down rapidly with heat.
..... And hydraulic fluid gets real hot real fast. Also, radiator hose clamps ARE NOT GOOD ENOUGH!
I'm an engineer. I only know of one high pressure hose that is clear, and it isn't near good enough for your system.

Your PTO pump is probably putting out somewhere between 1500 and 2000 psi. A small leak will cause that fluid slice slice through your flesh like a water jet cutter.
You can't see it coming and nobody is fast enough to get out of the way.
It sounds to me like the way you are going about this is just way too incredibly dangerous. Lets talk about it.
rScotty

 

[elkmtngear]

You can't see it coming and nobody is fast enough to get out of the way.
It sounds to me like the way you are going about this is just way too incredibly dangerous. Lets talk about it.
rScotty

Point taken. I just ran it for maybe a minute, to see the direction of flow (I had read that some of these Chinese pumps could be built "reversed"). I won't try it again.

 

[oldnslo]

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.

 

[rScotty]

Point taken. I just ran it for maybe a minute, to see the direction of flow (I had read that some of these Chinese pumps could be built "reversed"). I won't try it again.

Good on you. You had me scared.
rScotty

 

[elkmtngear]

Reservoir and hoses are all connected to the backhoe (only) from the pump

 

[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.

Inlet and outlet hoses are coming from the backhoe (only). It has it's own reservoir (filled it before I started).

 

[oldnslo]

Have you used the PTO for other implements or is this the first time running the PTO?

 

[elkmtngear]

Have you used the PTO for other implements or is this the first time running the PTO?

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

 

[dfkrug]

I would say definitely "milky".

Oh-oh, water in the oil.

This is probably unrelated to your PTO pump system. Water got into the sump, possibly from a torn shifter boot, and the volume of oil/water is such that it overflows when operating the loader.

This photo shows what came out of the shifter boot when I ran an old neglected Kubota I picked up this summer.

 

[elkmtngear]

Oh-oh, water in the oil.

Probably impossible. This Tractor is stored in my Workshop Year Round, and is never left out in the weather. Like I mentioned earlier, I never had this leak until I hooked up the backhoe. It seems the "milkyness" could be from air pressure (possibly from the pto pump)?

 

[rScotty]

Oh-oh, water in the oil.

This is probably unrelated to your PTO pump system. Water got into the sump, possibly from a torn shifter boot, and the volume of oil/water is such that it overflows when operating the loader.

Yep, that looks typical. When water mixes with the oil you always get an emulsion that looks like milk after it gets stirred up. The color can range from dark chocolate milk to as white as your picture....but that's water sure enough. I've wondered if the peculiar milkiness is due to the detergents in modern oil.

Trans/hydraulic oil doesn't see any combustion and there isn't much inside a tractor to contaminate it. Generally it should look the same after 1000 hrs as it did new.

And yes, the shifter boot is the prime offender. It's crazy that they aren't better sealed. Also, if you have milky trans/hydraulic fluid you may also find water in the steering box at the base of the steering column. Water can enter the center of the steering wheel nut and fill up that steering column until it eventually makes it past the bearing seal into the steering box.

Both problems are so simple to avoid by simply putting a tarp over the tractor when it is left outside. That's all it takes.
rScotty

 

[elkmtngear]

Both problems are so simple to avoid by simply putting a tarp over the tractor when it is left outside. That's all it takes.
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.

 

[CADplans]

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,,,