john deere 310c weak hydraulics in loader lift, stabilizers, and boom mostly.

If all else fails just put a tee in a pressure line with a gage on it. Once you know the pressure it’s running at you can make adjustments or determine if the relief valve is bad. That looks like the type of relief that has a pilot valve adjustable with shims.

LarryH said:

If all else fails just put a tee in a pressure line with a gage on it. Once you know the pressure it’s running at you can make adjustments or determine if the relief valve is bad. That looks like the type of relief that has a pilot valve adjustable with shims.

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Thanks for the reply.
So, I could theoretically just put a t in one of the hoses going to the loader lift arm? I have some pressure gauges but no adapter to fit this machine.
This backhoe has the deere taper fitting looking connections. I cant remember. What are they called?
I live in a small town. Where would I find a t that fits between a hose and the loader lift arm?
I find it odd that the relief valve housing doesnt have a dang port where you can use a pipe thread nipple to mount the gauge? I used to do that on old Case backhoes back in the day....
I doubt my local NAPA has any kind of line T. Grrr....

So, when i do test pressure, and it shows low, i add or remove one of the two shims? And if that doesnt help then i know its the relief valve or the pump? Or, should i then replace the relief valve anyways before i consider buying a $4600 pump?

Thanks so much

No normal test ports.

Maybe I could find some sort of a T to go in one of these lines to the loader loft arm cylinder? But would I have to have the loader lift valve open using the joystick to see pressure reading?

Wrench size is 15/16. Can’t remember name of fitting style. JIC?

The size really doesn't tell you what the fittings are. Those don't look like JIC connections to me but might be. It's always best to remove them and see what they are. Does the technical manual have a hydraulic diagram for this tractor? That would be the place to start. Locate the high pressure line coming from the pump and find a convenient spot to splice in a tee. You may have to visit your dealer to get the fittings you need unless you have a hydraulic shop near. If you can watch the pressure while working the machine you may be able to diagnose the problem.

LarryH said:

The size really doesn't tell you what the fittings are. Those don't look like JIC connections to me but might be. It's always best to remove them and see what they are. Does the technical manual have a hydraulic diagram for this tractor? That would be the place to start. Locate the high pressure line coming from the pump and find a convenient spot to splice in a tee. You may have to visit your dealer to get the fittings you need unless you have a hydraulic shop near. If you can watch the pressure while working the machine you may be able to diagnose the problem.

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Thanks for the reply.
It my logic, it seems as though I’d wanna splice into the main pressure line before it goes into the block where the relief valve is located. And then move the t to the outlet side of the block that is AFTER the the relief valve. But as far as the AFTER or outlet side of relief valve block, i assume the accessible outlet side of the block is a return to the pump. So I’d be better off moving the T and gauge to a like coming out of the loader valve and cracking a joystick valve to see pressure when valve is open. The return line to pump would show ...well...maybe I would want to know that pressure as well.

My service manual leaves out the hydraulic circuit diagram. Odd huh? But luckily, the hydraulic system is kindof laid out simply on this machine it is a basic 310c with no extra features.

So, I yet to understand why there is a mystery as to what is considered a rebuild of this pump. A 5 Oring kit from Deere is what they call a rebuild kit. So, no gears or anything within the pump are needed for a rebuild.

An interesting thing I notice when my machine is running there is this pulsing vibration/ harmonic sight feeling I feel in the machine. It’s a pulsing thing that almost feels like something is out of balance in the the pump that pulses in and out in 1 second pulses. It doesn’t seem to be the engine.

Post # 8 has the procedure and fitting sizes which connect to the port below. And yes, the relief valves are obsolete through Deere. You will have to source them elsewhere. Google search AT118707 for serial number 752244 and down, or AT117647 for serial number 752245 and up.

mg2361 said:

Post # 8 has the procedure and fitting sizes which connect to the port below. And yes, the relief valves are obsolete through Deere. You will have to source them elsewhere. Google search AT118707 for serial number 752244 and down, or AT117647 for serial number 752245 and up.

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Omg! You are a lifesaver! I literally was looking back at my pics and just was gonna post a post asking if that spot could be it! I don’t know how I overlooked it when I was physically in the presence of the machine but I was looking back at the pics for the “Husko” brand and part number and googling why or what the upgrade was and the thought hit me! Could it be and boom...u sent your reply! I guess I may have originally thought that weird spot was part of the assembly or where it connects to loader valve assembly inside...o ring access or something.

I saw where you had marked on the photo and I just tried to mark on the photo using my iPhone. I didn’t know marking on a photo was so easy. I learned multiple things from your reply! Thank you!

You must have lots of experience. Idk why Deere has left these old machines out to pasture on parts. I thought the whole reason for buying a brand like Deere was because of parts availability....

Forget that. Shoulda bought a dynahoe lol

Here is my attempt at marking on a photo:

mg2361 said:

Post # 8 has the procedure and fitting sizes which connect to the port below. And yes, the relief valves are obsolete through Deere. You will have to source them elsewhere. Google search AT118707 for serial number 752244 and down, or AT117647 for serial number 752245 and up.

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I’m so stupid I didn’t realize you had sent me the info back in the beginning! The PDF!!

So I’m googling the adapters. Not sure if I need one or both. Haven’t found the on eBay, Amazon, or google yet. Must be a Deere item?

So I must pull that plug out and install adapter and then thread a standard hydraulic pressure fluid filled gauge in. I have some 0-10,000 psi gauges and some lower psi gauges. I last used them on a d3 cat pedal steer diagnosis situation. No quick couplers...just raw gauge with brass nipple sticking down...

bill fold said:

what is the inline fuel filter looking thing that appears to be coming from the tank vent?

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Those fittings are Deere part numbers. If you want to source those fittings elsewhere try looking using the fitting sizes.
Forgot to answer your question on the little filter, yes that is a tank vent. The filter just keeps dirt from being sucked into the tank when the tank is "breathing". As far as obsolescence, I think they do that so you buy a new machine. When a machine gets to certain age (it varies) Deere stops supplying/making parts.

I think what you want can be googled using 6400-4-4 fitting. You can then look for a diagnostic coupler to connect to it or just connect a hose directly from your gauge to it.

Well. I finally got the adapter. It took two tries on amazon. They sent the wrong part.

It’s a 6400-04-04-0-SS

So, according to the service bulletin, it says to check pressure at fast idle. I’m getting 0. When I crack the loader valve joystick it raises slightly on the gauge.

I backed the top cap off on the relief valve further than what seems normal. No change.

Also, does the relief valve factor into this test port? It seems that if it’s coming from the main inlet it would be just pump pressure. But I’m a way I can see how the relief valve may stick down into the body to where the port is and move flow toward the outlet or back to tank?

Hmmm.

bill fold said:

So, according to the service bulletin, it says to check pressure at fast idle. I’m getting 0. When I crack the loader valve joystick it raises slightly on the gauge.

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mg2361 said:

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Thank you so much for the tip. I tried to do what you said. All I could get was 1200psi.
I adjusted the relief valve. No change!!

I tried to be safe about the adjustment. I’d cut engine off relieve pressure on hydro system and then turn the top adjustment cap one round wash time. Then crank it back up.

No change each time.

Here is the embarrassing part...
I walked away for a second to pick up a wrench or something...all the sudden the hydraulics shot out of relief valve! The top cap must have been on its last thread of adjustment and vibrate loose shooting fluid all over my shop! Luckily I wasn’t near it but it still got all over me! I couldn’t get to the switch! It was spraying over it. I had to grab a steel bar and ready I’ve into the cockpit and bump the ignition key off! Omg what a mess!

Well, seems to me the relief valve isn’t adjusting pressure properly. I ordered the one and only that I could find off of eBay!

Waiting on it to come.

Ok, so this may be an undiagnosable relied valve issue? It looked fine when I took it apart to clean it.
But also, what in the hell is the weird pulsing sound and vibration this thing makes at high rpm. Engine seems fine. Some kind of pump surge....

And by the way. I’m so frustrated with the dealer.
The parts guy can’t sell me fittings or tools. That has to be sold through the machine sales. The machine sales guys don’t answer the phone and when one does..he doesn’t have a password to log in to the tooling sales website??? Only one guy has that password and that guy can’t be found.
Everyone at Deere tells me to call parts. Parts tells me to call sales. Sales tells me to call parts. Parts tells me to call shop service.


Most parts are discontinued!

And so, if my pump needs to be rebuilt...John Deere’s rebuild kit is only orings and seals. No hard parts.
I look online all over for Sundstrand Sauer hard parts for pump and can’t find anything. Only lawnmower stuff.

What a mess. Where does one find Sundstrand parts?

Thanks for the help so far.
Waiting on relief valve.

At this point I have to advise you to STOP! it is time to hire a professional whether it be the dealer or an independent to do an evaluation of your pressure and flows. Thank goodness it was only an oil bath. It could have been worse.

So what was the culprit of your issue?

Looks to me like you also have circuit reliefs did you check pressure at a function that you say is stronger