Loader refurbishing worse than when I starte

[Xfaxman]

--------------------------------------------------------

Not sure what to make of this. I brought this up in the Yanmar forum back in the summer. This model does support a front PTO but that's not what I've got. There's no clutch or anything just a shaft sticking forward from the engine that can be coupled to the pump. I kinda doubt there's another one in the world setup like this. It looks like a custom job to me. I didn't move the pump so I think it's installed right where it's supposed to be. :thumbsup:
----------------------------------------

I am guessing that shaft is connected to the crankshaft. This was a common add on many years ago when adding a loader to a Ag tractor.

I wonder if the pump is a 540 RPM PTO pump. Is the pump shaft smooth or splined.

You mentioned shear bolts, so probably smooth.

Does the tank bubble over when the engine idles?

 

[woolyAcres]

I am guessing that shaft is connected to the crankshaft. This was a common add on many years ago when adding a loader to a Ag tractor.

I wonder if the pump is a 540 RPM PTO pump. Is the pump shaft smooth or splined.

Here's a photo of the front pump and the shaft that sticks forward from the engine and engages it. I use a rubber bushing and some shear bolts to couple the engine to the pump. This shaft turns at the engine rpm not the rear PTO speed (540).

Does the tank bubble over when the engine idles?

It will eventually. After about 3 minutes of running today it had not yet bubbled over, but the top of the level went up about an inch in that time. Leaving only another inch before it would have overflowed.

 

[woolyAcres]

I tried removing and tightening all the fittings around the pump itself. That had no effect. I removed the high pressure line from the loader valve and put it straight into the tank, it still bubbled. So I was left with nothing to do but remove the pump. Doing so did allow me to find some small numbers on it. It appears to be a Cross 5Z420.

I don't know much about pumps so I'm not sure where to start. I guess finding some specs on this would be a good place....

 

[Xfaxman]

Looks like it is a series 40: Gear Pumps and Motors - Cross Mfg.

Six sizes:

 

[GPintheMitten]

Here's what I found on that number. Says left hand etc.

Cross 40 Series Gear Pump 40P005-LACSA - Gear Pumps & PTO's

I see Cross does offer seal kits.

 

[GPintheMitten]

So the pressure line had bubbles coming out when you put it in the tank? What do the experts say? (I'm not one,)

Does that mean pump seals, leak in suction line? I see that if the pump is spun backwards, the seals are damaged immediately. Also you can get higher pressure seals. Shrug?

 

[LD1]

So the pressure line had bubbles coming out when you put it in the tank? What do the experts say? (I'm not one,)

Does that mean pump seals, leak in suction line? I see that if the pump is spun backwards, the seals are damaged immediately. Also you can get higher pressure seals. Shrug?

Not really a good test IMO.

Bubbles at start up could just be where things have leaked down. But continuing bubbles could be for the same reasons why I recommended lengthening the dip tube for the return line in the tank.

Simply sticking a return line in the top of the tank induces alot of air into the system, then the pump starts pumping air, which when it returns induces more air, etc etc. its a never ending cycle.

Just think about holding a glass of water under a running faucet. (and Im not talking about an aerator type). Look at all the air bubbles that running stream pulls in. Same thing with sticking the hose in the top. A very inconclusive test for tracking down air.

 

[oldnslo]

Unfortunately the 5Z420 means nothing, it is a casting number and not a valid model number. Also could not find any info on where a model code could be.

I also could not find any dimensional information to see if the different displacements had a different overall length. I suspect they do but not sure. The 0.5 cubic inch would provide around 2 GPM at 1000 RPM and 4 GPM @ 2000 RPM. This would be a reasonable match to a 4 gallon reservoir.

Where is this return line port in relation to the pump inlet port on the reservoir? Directly below it, opposite corners, etc.

Is the a baffle in your reservoir?

Like LD1 stated, if the return is above oil level it will aerate the oil especially in this small of a volume.

How does the shaft & seal area look on the pump? Is the seal dry and hard or pliable?

Is the shaft all rusted and corroded? Kind of looked like it on the pictures but not sure. If the sealing area is rough you have problem.

This link is for the service manual on this pump. It also provides some model codes.

Gear Pumps and Motors Technical/Service Manual - Cross Mfg.

Note: This also states the inlet hose should be 3/4 inch or larger.

 

[TomSeller]

That "return line" he is talking about that gies 4" inti the fluid is the fluid coming BACK to the tank, not being sucked TO the pump. See previous picture of the pipe where the fluid leaves the tank, it is way down at the bottom.

 

[TomSeller]

Looks like it is a series 40: Gear Pumps and Motors - Cross Mfg.

Six sizes:

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=454267"/>

That pump says it is rated up to 17.5 GPM depending on cu in per rev.. Joystick valve is rated at 10 GPM. May not be what you want.

Try leaving the tractor at low low idle as asked above, if that is not what you already did, and see if there is foam.