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The only good news in this bowl of crap is the cost of the pump. It came with the tractor NIB. I can't return it of course, but no out of pocket for this one.

I guess I'm shopping for a new pump. Any ideas?

I'm going to do an autopsy on this one just for grins and a need to know what failed.
I would do autopsy. I bet a drive Pin / key is sheared.

where is your relief valve in the FEL circuit or pump circuit? does it have one? Could either have been stuck and pump pressure was to high to handle and shear the Pin / Key internally when you was deadheading to bleed air? It will shear fast with no sound or sign if pressure is not manage correctly.

Tim
 

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Discussion Starter #642
I'm hoping the pump got jammed with all the gunk in the cylinders. With any luck it just needs cleaning and a reboot.

For those who may not have seen the beginning of this journey - this is what the hydraulic fluid looked like when I opened everything up.

2464331


2464332


2464333
 

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Discussion Starter #643
I would do autopsy. I bet a drive Pin / key is sheared.

where is your relief valve in the FEL circuit or pump circuit? does it have one? Could either have been stuck and pump pressure was to high to handle and shear the Pin / Key internally when you was deadheading to bleed air? It will shear fast with no sound or sign if pressure is not manage correctly.

Tim
I don't believer there is a relief valve - or it's built into the FEL control valve. It may have been both gunk and over pressure.

What, how and where would I install one? Examples?
 

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I don't believer there is a relief valve - or it's built into the FEL control valve. It may have been both gunk and over pressure.

What, how and where would I install one? Examples?
I was looking at past picture in this post and it looks a lot like the GT 400 valve which I think is a Cessna. attached is a break down of the stock valve on the 400. By looking at your picture the backhoe valve looks to have too. I would make sure both are ok once you have pressure to check with a in line gauge.
 

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Discussion Starter #645
Excellent Tim - that's what I needed to be sure of what's inside and how it fits together. Will pull the valve apart again and try to find what's hanging it up coming out of the float position.
Will disassemble the pump and see if it's gummed up and/or pin is sheared. I would think it's repairable.

Have to turn my attention back to the house remodel for a few days to finish up some things.
 

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You had me at rotation..... The pump spec is CW, however, which way do you look at it?
  • If I am standing in front of the tractor looking at engine and pump - both are CCW
  • If I'm looking at the engine and pump from the seat of the tractor
To determine direction of rotation, view the end of the shaft when it is pointing at the observer.

In this case, with the shaft of the pump pointing towards the shaft of the engine, the correct rotation is engine CCW and the pump CW.

Relief valves are fail safe devices. In the event that a failure occurs, the system is safe. Failure can be caused by debris trapped between the poppet and the seat which allows flow to return to tank, or a broken spring which will result in the same scenario.

Overpressure can only occur if the poppet remains seated due to excessive shimming. In extreme cases, this will result in a cracked or broken pump case and an unholy mess of hydraulic fluid sprayed around.

Normal relief valve locations are :
  • immediately after the pump and before the first control valve,
  • integral with the first control valve set (visible on the outboard side of the loader valve set, and on the right side of the back hoe valve set).
The first relief valve noted above is a system relief valve. It does away with the necessity of a power beyond kit in a control valve with an integral relief valve. It has an inlet port for fluid from the pump, an outlet port for fluid to continue downstream to the control valve set(s), and a return to tank port to direct overpressure fluid back to tank.

In the absence of the above noted system relief valve, the use of integral relief valves in conjunction with two or more control valve sets necessitates the addition of a power beyond kit for the first control valve set in the primary circuit that supplies fluid for subsequent control valve sets down stream, as well as a return to tank line from the first control valve set to handle fluid dumped when the relief valve pops. This relief valve governs maximum system pressure.

Subsequent integral relief valves in control valve sets down stream cannot be set for a higher pressure. They can be set for a lower pressure to limit loads as necessary.

Was the discoloured fluid in the pan actually dirty, or was it caused by emulsified air in the form of tiny bubbles?
 

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To determine direction of rotation, view the end of the shaft when it is pointing at the observer.

In this case, with the shaft of the pump pointing towards the shaft of the engine, the correct rotation is engine CCW and the pump CW.

Relief valves are fail safe devices. In the event that a failure occurs, the system is safe. Failure can be caused by debris trapped between the poppet and the seat which allows flow to return to tank, or a broken spring which will result in the same scenario.

Overpressure can only occur if the poppet remains seated due to excessive shimming. In extreme cases, this will result in a cracked or broken pump case and an unholy mess of hydraulic fluid sprayed around.

Normal relief valve locations are :
  • immediately after the pump and before the first control valve,
  • integral with the first control valve set (visible on the outboard side of the loader valve set, and on the right side of the back hoe valve set).
The first relief valve noted above is a system relief valve. It does away with the necessity of a power beyond kit in a control valve with an integral relief valve. It has an inlet port for fluid from the pump, an outlet port for fluid to continue downstream to the control valve set(s), and a return to tank port to direct overpressure fluid back to tank.

In the absence of the above noted system relief valve, the use of integral relief valves in conjunction with two or more control valve sets necessitates the addition of a power beyond kit for the first control valve set in the primary circuit that supplies fluid for subsequent control valve sets down stream, as well as a return to tank line from the first control valve set to handle fluid dumped when the relief valve pops. This relief valve governs maximum system pressure.

Subsequent integral relief valves in control valve sets down stream cannot be set for a higher pressure. They can be set for a lower pressure to limit loads as necessary.

Was the discoloured fluid in the pan actually dirty, or was it caused by emulsified air in the form of tiny bubbles?

Tudor

your correct on the relief valve are fail safe devices in a normal build application. Not only protects system components, it control heat in the system and people from trying to work with pay loads the equipment is not design to do or being stable in the stability triangle. A lot of this goes out the window when People are introduce.

Most, but not all relief failure being of high pressure I've seen, have been people conflicted. Yes most the time it is a crack housing with the older heavy built pumps. The newer gear pumps I have found the drive key are shearing with the gear on the input drive shaft. Only mention this to Toaster Tan because this tractor looks as it has had a lot of hands on it. Toaster Tan had some question on the detent balls that fell out of the spool and leads to me that he is working with the part as-is with out a parts break down view. This is not picking on Toaster Tan anyway.
 

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The ONLY 400 tractor I found nationwide with a backhoe just had a blade on the front. I looked at ads over a wide geographic area around me for a LOT of other brands and none had both attachments with a price anywhere near this. Figure I'll spend $1,000 - $1,500 to bring it to great condition. I have a good shop, airless spray rig, large media blast booth, MIG welder, tire changer, steel bender, tube bender and other tools for this.

Can you show me where another one is? What can you show me for comparative pricing of a 400 with backhoe, front loader and front blade? I've had 3 offers in the last two weeks of over $3,000 for the backhoe, as-is.

I need it to dig up a septic tank with possible repair to the drain field. Also going to make drainage channels for runoff to a small holding pond. Clearing about 1/4 acre, moving some dirt to fill low areas and create landscaping. Regrade and expand a driveway, including new crushed rock. A contractor wanted $2,500 to dig up the septic, not counting any repairs. Landscaper wanted between $8-10,000 for the other work. It's $1,200/week to rent the equipment. With both JD-318 and 400 I can do everything myself - at my own pace.

The math works great when you consider resale price and money saved. That's not even considering the fun factor! http://www.mytractorforum.com/images/MyTractorForum_toucan/smilies/tango_face_grin.png
What kind of value do you put on the tractor and blade?
 

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Discussion Starter #649
OK - I've had to focus on other things for the past week, but will pull the pump and autopsy tomorrow.

Got a cash offer on my house, but it occurred to me this may not be the most opportune time to move to Phoenix Arizona... Just guessing, but think finding the right place to buy might be slim pickings and would be distracted by other things - like staying alive. I live 15 miles from original ground zero in the US and it's rural enough to easily keep isolated. Moving to AZ would be like going from the frying pan to the fire - to an inferno in a bathing suit.
 

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Discussion Starter #650
Dan -
I have no idea what the market value would be for my rig as there are a number of variables. Like everything else - it's worth whatever someone will pay for it.
 
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