Okay guys I need some help. not sure what year but late model 310a deere. The hydraulics are very slow and it won't do two functions at same time whether its backhoe or loader. The main pummp is new,filters new and checked suction screen in trans. I do know I have a control valve bypassing on backhoe main boom and possibly loader bucket. What I'm wonder is there anyway to check charge pummp without splitting tractor in half? On the main pump I've checked pressure at the two ports on right side and pressure is good on both ports. Please HELP.
Does anyone have any ideas to check other than charge pump
If preasure is at factory specs at control valve or at pump you have already checked charge pump most jd use varible piston pumps and won't pump with out charge pump ,,maybe pull spools from control valve to see if spool is broken if you belive oil is crossing in system
Here's a link to the spec sheet. http://www.deere.com/en_US/cfd/cons...non_current_pdfs/noncurrent_backhoes/310A.pdf It says the machine has closed center hydraulics and a high stanby pressure. Maybe an internal load sensing piston pump? :beatsme What makes you think you have control valves bypassing? Care to elaborate on that?
Thanks! I've been told that if charge pressure is good then nothing wrong with charge pump. Could charge pump not have enough flow but still have correct pressure?? I disconnected the feed lines to backhoe and plugged them but had no effect on loader operation. If a loader control valve is bypassing will this slow down loader and not let it do two things at one time? The longer I run it the worse it gets.the loader is worse than backhoe but I know for sure main backhoe boom valve is bypassing.
At one time I had the tech manual for these machines. In the control valve section it says the control valves do not let oil pass through unless valve has been actuated so what I did was disconect the lines from valve to cylinder and cranked it up, oil shot out of valve passed backhoe boom
I don't know the 310A hyd circuit, can't help ya much with specifics of the machine, and the Deere site only has spec sheets, no schematics. I can only say to have a 2,300 psi standby pressure on a closed center circuit; you can only do this one of two ways. 1) fixed displacement pump (like a gear pump) with a differential sensing valve (a flow control valve of sorts) or, 2) variable displacement pump (piston, axial, hydrostat, a few names) with either internal load sensing or external load sensing circuits. The first thing you would do is check to see if you have the spec standby pressure. You mentioned the longer you run it the worse it gets. Is that with every use it gets worse? Or; as you use it, it gets worse, shut it down, next day it's working, then as you use it, it gets worse? BTW, I just read your last post, gotta noodle that in my head.
It has variable displacement piston pump. What I meant is the longer I run it the worse it gets then shut it down let it cool off and its as good as its gonna get. Even when its cool it wont do two things. What do you think about charge pump not providing enough flow but has correct pressure? I forgot this the charge pump is a fixed displacement gear pump in trans there is a pressure control valve mounted on side of trans. I don't remember just what it does.
Man you got a crazy problem. And it don't help that I don't know the hyd circuit of the machine! And...I've never seen a combination of problems that you are describing. The charge pump; If you got on the machine, raised the loader arms, lower them, raise them, lower them, maybe even drop the bucket on the ground and raise the machine by lowering the arms. If it will do this, I doubt you have a charge pump problem. And, if I understand you correctly; as you run it...it gets worse, then, after cool off, we're back where we started to do the same thing over again. That sounds like a problem related to heat, whether from a worn pump or malfunction of a valve, not certain which yet. And this doesn't even address the problem of not being able to run two functions at once, I haven't figured how these two problems connect yet. BTW, does the hyd circuit work the steering? Or is it a seperate system with its own pump? If hyd systems steers it, how well does steering work? Just curious. I think I'd check the standby pressure, whatever it is, and note it at startup. And check the case drain at the pump at start up. Connect a hose to the case drain fitting on the pump, place hose in an empty bucket, and start engine. Note how much oil goes into bucket in a minute. Then, run the machine until it craps out. What's the standby pressure now? Connect to the case drain, how much goes into the bucket now?
Hey tell me about it! I've been pulling my hair out dpe awhile now. I don't remember how its all connected but it does have hyd steering. Attached to bottom of steering column is a pump or either some type of directional valve that sends oil one way or the other. I've had some older guys that worked for deere when these were new tell me that when i change the reverser from foward to reverse if it changes directions without hesitation that its not charge pump. Mine does this fine. Then I've got guys tell me can't be nothing but charge pump. This is really gotten me. I'm a industrial millwright and deal with hydraulics but not like this. Oh I keep forgetting stuff! If while steering I work the backhoe the steering gets tight for just a second. Working the loader has no effect on steering.
Wow would I like to see a schematic right about now! That thing at the bottom of the steering column is called an orbital valve. As for the loader and hoe having different effects on steering, I'm getting overwhelmed with info. These are all clues to what the ultimate problem is, and one's I would ordinarily take note of, but the lack of knowledge of this system is a detriment for me in this case. Let's keep it simple for the moment, unless a Deere tech jumps in here to help us out. Let's check the pump like I said earlier and see what info that gives us. And, if "old Deere techs" told you this about the charge pump...I believe I would yield to their experience for now.
Okay I will do it monday as I am away this weekend
To clarify what the spec sheet says about your machine, it's a "closed center" hyd circuit. That means, when no control valves are being operated, everthing in neutral, the control valves are a hyd dead end. The control valves, in neutral, do not allow oil to flow to cylinders, and there is no return to tank as well. It's a flat out dead end for the oil. That's where the pump develops the 2,300 lbs standby pressure. The hydrostat pump delivers oil. But since it's delivering to a dead end, oil ain't flowing. Pressure builds, until it reaches 2,300 lbs. Once that's achieved, the pump moves the swash plate and "destrokes" the pump and quits trying to deliver oil (flow). It holds the swash plate at a position that simply maintains this 2,300 psi of pressure against a dead end with no oil flowing. Then, you select a function (raise arms), that activation of a function causes the 2,300 lbs of pressure to drop, because now oil is flowing (to the raise arms function). The "sensor circuit" of the pump notices this pressure drop and moves the swash plate to produce more oil flow to compensate for demand. That's pretty much how your system works. It doesn't begin to understand your problem. But you have to know how it works before you can understand what the problem is, and we haven't even got into the "power beyond" of the valves that allows you to work more than one function at one time. We'll get into that later.
did you put a presure gauge on the lift arms or the hoe to see what working presure is at the cylinders in question if bouth are low presure not to specs yes you have a problem .I belive you need a flow gauge to check flow volume from pump ,you might talk to dealer on some j d pumps there is an ajustment externaly for presure ,,,,But with out proper gauges you can hurt pump or weakest link with to much presure, If done wrong
I haven't tried gauges on cyl or control valve. A flow meter would be great but these are pricey.I've been told how to do flow check shade tree style by taking filter off and placing a bucket under tractor with some gallon marks on bucket. They told me crank tractor and let charge pump oil flow into bucket for like 10 seconds see how much oil is in bucket and multiply by 6 and that will give me charge pump flow for 1 minute. However not to sure about this. What do you guys think?
I wouldn't do that youre looking at a $ 2 to 3000.00 doller pump and you have a expensive core charge if you run pump dry it moves alot of oil if you have to change it .you want a good core ,,,you could check case drain like atco said but with out real numbers or p.s.i. you can spend a lot of money and still fix any thing ..what i would do go to parts store and buy at least a 3000 psi oil filled gauge put it on the line to lift cylinder on boom run till starts to loose power check gauge do same for hoe cylinder ,,,,if preasure is 500 psi under spec sheet you have a pump bad or needs ajust ment ,,if you talk to a knowageabul shop guy he could tell if ajustments can be made or a rebuilt pump will fix
I will try that also. My main pump is new or it has less than 50 hrs on it now. Any idea how much acceptable case drain flow should be?
Don't think that will work on this machine. Remember, the spec sheet says you have a closed center circuit and 2,300 psi standby pressure. This means when it's running and no functions are being used, all valves in neutral, there is no oil flowing out of pump, and no oil is returning to tank via tank filter line. The oil in the pump output line is static, at 2,300 psi, until you work a function, then the oil flows from pump, and the pump increases output according to the demand of the function being operated. Whoa! Are you saying your main hyd pump for the machine has less than 50 hrs on it??? At what point did you begin to have these problems?
Yes the main pump is new. The machine was doing this when I bought it so I replaced pump.this is why in my mind I've kinda ruled out main pump and focused on charge pump now and control valves. When I said I took lines off vontrol valve for main backhoe boom and oil shot passed boom am I correct in thinking the valve is bypassing
My bad...I went back and looked at your original post, you did say you replaced the main pump. Man...too much junk in my head! :Banghead I'm still trying to figure out how oil shoots out that far when you took the boom hoses loose. The A and B ports of a valve are blocked from the supply when in neutral, whether the valve is open or closed center. Yes, it's normal to have a small amount of leakage (bypassing as you refer to it) between valve spools and bore of valve body. Obviously, if the spool was so tight inside a bore that no leakage would happen, it would be so tight you wouldn't be able to move the spool. What you would normally see if you took the two hoses off of the valve body that controls the boom with the engine running is a small amount of oil flowing out the hose ports. If the spool was broken, you wouldn't be able to boom up and down. One function, either up or down, would not work. Man would I love to see a schematic on this machine. I've serviced a number of 310's, just haven't had to do hyd repairs on one.
Yea I can't figure out why so much oil was coming out of that valve either.but I still believe I've got one bypassing like this on loader bucket also.
I gotta get in my head how your machine works. I remember on the 310C and 310D the hyd pump got it's oil from a reservoir tank. On your A, does it come from a tank, or from the transmission sump? If it comes from the trans, does a charge pump feed oil to the hyd pump? What about the pressure supply line that leaves the hyd pump to valves, what valve does that line go to first? How are the pressure supply lines connected from hyd pump to steering, loader valve, and hoe valve?
Yep the charge pump feeds the main pump oil from the trans sump.I'm not at home so I can't look at tractor but from memory oil leaves main pump and goes to pressure control valve mounted on side of trans.from there oil goes to loader and backhoe control valves from two seperate ports on pressure valve.now I belive oil is feed two reverser then then brake valve by charge pump but this all I can remember. And like you I have no scematic to go by very frustrating.
Hmm, that's a funky system you got goin' there. If you have a charge pump to feed oil to main pump, the you probably do have a variable displacement hyd pump. Positive displacement pumps generally do not need a charge pump to feed them. The valve on the side of the trans; I don't know that it is a "pressure control" valve. Pressure control would be done internally at the main pump, unless there is a compensator line going from valves to hyd pump to control position of the swash plate. What feeds oil to the steering orbit valve? What feeds oil to the brakes?
Not sure about brakes and steering,maybe charge pump but I don't know for sure.however the pressure control control is supose to dump oil back to sump if system pressure builds to high.there is no way I can double check this0to be sure.man I wish I still had that tech manual!!
Whats your serial number and arrangement number, will see if I can get some info for you
That would be great! Ill try to get monday.what do you mean by arrangement?
On the serial plate there will be the serial number and possibly an arrangement number which is like a build number of your machine which shows what was as shipped when your machine left the factory, let me know and I will look into it for you.
Okay not sure if this is serial # or not.this tag is on frame that holds motor the number is 310AD 375925T I don't see any other number that would be arrangement number. Let me know if this is wrong and I will look for something else thanks.
Okay I did a little test today.I let tractor idle for about 20 minutes with both trans levers in neutral and reverser also. The trans filter cover got hot and the main pump and reverser also.both loader control valves were fairly hot along with pressure control valve or priorty valve. The brake valve stayed cool. Any ideas if I'm on to somthing here or are these supposed to get hot?
Excessive heat is "generally" caused by fluid moving through a restiction of some sort. Could be a blown seal somewhere, could be a valve malfunction, could even be some other cause. By the way, I talked to the service mananger at my local Deere dealer, he e-mail me some info on the hyd. system. It was a HUGE file, PDF. I couldn't even get it to send to my home computer it was so large. But I mananged to cut the first 15 pages and send it. I'm going to attempt to e-mail it to you some time this evening.
Okay that would be great!!
What about the steering orbital valve and the backhoe control valves, did they get hot as well? Also, this test, you did this with machine idleing and in neutral; did you operate any functions or leave them idle as well?
have you checked for a collapsed hose going to or from the oil cooler? Also there is a filter from the charge pump to main pump. It is located down under on I believe the left side and looks like a large bolt. Do a search on here for 410jd issues. We had a similar thread by awhelan? many of the same types of issues with charge pump. If I knew how to link to it I would.
Okay guys I did run loader and back hoe a couple times during my little test. I couldn't get to steering valve without pulling all of floor up. The backhoe control valves got maybe lukewarm with main boom valve getting the warmest however the rubber lines comming off valve to cyl stayed cool.now I'm really confused. Yesterday I hooked my gauges up to main pump. Results are at idle standby pressure 2300 psi at 1900 rpm 2300 psi.operate loader function pressure drops to 1000 psi regardless of rpm. Now charge pressure at pump is lower than I remember at idle 60psi at 1900rpm around 80psi. I was going to check charge pressure at reverser but I didn't have right adaptor to put gauge in. I also pulled trans filter bypass relief valve but found no trash in it.hey bill onthehill I have looked for collapsed hose but no luck. I found the post you referd me to.
Wow, there's a lot of logic to put into this one! First of all, I'm still trying to get info on the 310 series from my Deere dealer. I got info on the 410 series and sent it to you, but I have a feeling the 310 series works very similar. Your 2300 standby pressure sounds good, but the drop to 1000 when you operate loader? Hmmm, that shouldn't happen. The pump should adjust and try to maintain the 2300 lbs standby pressure and then some for the load being applied. Could it be the charge pump is not delivering enough oil to the main pump, therefore, we get pressure drop when operating a function? That's logical...but that doesn't create heat. Like I said earlier, heat in hydraulics is generally generated by resitance to flow, not lack of flow. Since none of us here appear to be Deere experts let's do this; let's work with the heat. That's the easiest clue for us to deterimine where the problem lies. I have other ideas, but let's do this first. Start machine and let it idle. Don't operate any functions. Constantly check pump and every valve for heat generation as the machine runs. If all components were good, there would be no heat to any component after 20 to 30 minutes of running. But, let's say, after 20 - 30 minutes, the pump, priority valve, and the loader valve are warm/hot, and the backhoe valve and steering orbital valve are cool, we're beginning to narrow it down and we'll narrow it further from there.
This sounds good to me. However I'm gonna check charge psi at reverser hopefully tomorow. I did find out the reverser is feed oil by charge pump and to get a good idea of charge pressure I need to check here.
I think you have a broken or weak relif for pump or control valve ,,when you checked pump preasure did you move bucket or some thing hoe? and check peeasure when cylinders are moving evan a piston pump needs relif to stop building preasuere and a relif can be weak or broken but when relif is weak you canno't tell by looking at it and lose operating preasure ,,,hope this helps some
Hey Bama-Mill, I've been looking at the components on the 410 series, and I have a feeling there's at least some similarities between the machines. Earlier you said you unhooked a function hose from a control valve and you said it shot oil past the backhoe boom when you started the machine. I think this was caused by an anti-cavitation valve on that valve section, it would be a normal reaction, nothing wrong or unusual. Like I said, I think the systems may be similar. On the 410 series, all the valves are closed center, just like on the 310. And, there is no true "return to tank" porting from all the valves. The "return" ports actually return to the charge pump circuit, which is under pressure from the charge pump. Everytime you operate a function, the main pump delivers oil to the selected function, and the return from the other side of that function is sent to the charge pump circuit. As for you problem, I don't think it's your main pump, because you stated there was no change when you install a new pump. The oil is getting hot. I'm going to step out on a limb at this point and say you either have a failed relief valve somewhere allowing oil to pass under restriction, or you have failed o-ring seals on a valve cartidge somewhere that's doing the same, allowing oil to pass through under restriction, creates heat every time.
Sorry bentwrench, didn't see your post...my bad. I need to help you out a little here. A piston pump doesn't need a relief to stop building pressure. Stroking and de-stroking the swash plate in the pump controls pressure as well as output of a piston pump. This can be done by either internal control (within the pump) or external control (sensory circuiting). Yes, there "will be" a main relief valve somewhere in the hyd circuit, but it's there to keep things from exploding in the case that something malfunctions with the pump swash plate control, not necessarily to prevent the pump from developing too much pressure. Variable displacement pump hyd systems are fascinating how they control pressure and output of oil and how they so quickly react to changes in demand. You can stab a lever in and the pump reacts by moving the angle of the swash plate to dump oil into a circuit, then you can just let go of the lever and the pump instantly de-strokes the swash plate and decreases output, maintaining the set stand-by pressure. Fun stuff to work with.
Hey atco I think you and bentwrench may both be right! I'm looking at maybe pressure control valve could be part of problem but why would main pump get so hot? I'm going to check my lines going to and from oil cooler because it doesn't seem to be getting as hot as pump. Like its not coolling any oil.at least its good to know I don't have to spend $850 for a worn out control valve. Gonna try to test reverser presure tomorow.I finaly found fitting I need to hook up my gauge up I Think
Hey atco I think we getting it narrowed down! Finally got to test charge pressure at reverser. I've got 155psi which is what its supposed to have now as I said earlier I've only got like 60 to 80 psi at main pump so I'm losing like 90 psi between reverser and main pump.I think I've got a relief valve either weak or stuck between these two. What do you or anybody think??
Didn't go back and review posts; didn't you say the reverser was working properly? On the 410, after the oil leaves the charge pump it goes to the hyd filter, and there is a relief in the filter for hi-flow situations like rapidly working the backhoe boom.
Yes the reverser is working properly. on the filter for hyd main pump does oil go through filter before ut goes to pump or after it leaves it? I'm thinking it goes through before but not sure because I can't get in my head how oil flows in relation to filter for charge pump.
Don't know on your machine. I'm hoping my Deere dealer can come up with some info, I'm going to contact him again first of the week. Did you look at that PDF I sent you? It shows a flow diagram, is yours anything like it?
I did get file but couldn't print it because off printer problems going to try to get it today. If I remember right it shows oil lines on what would be left hand side if sitting in seat mine is not like this all are on right side but oil probally flows to same compontants regardless of piping. I just pulled reilef valves out of trans and main pump filters but didn't find any trash.
Are you certain your checking charge pump pressure at main pump? Is it supposed to be 155 charge pressure at main pump? Sounds like the 155 is to provide pressure to engage the clutch packs, but is it possible that the main pump doesn't need that much charge pressure? I don't know. Is it possible the reverser circuit also performs pressure regulating of pressure going to feed main pump. And I could be out in left field with this.
Yep you're right! I went back to john deere website you provided in you're first post and it says charge pressure is 55 to 135 psi at main pump.
If that's the case, and the flow goes from charge pump, to reverser, then an outlet line from reverser to supply main pump at a lower pressure; then there must be some form of pressure reducing valve in the reverser. They work similar to a pressure relief valve, but gererally aren't as restrictive when they open and dump fluid as a relief valve usually is. I doubt your problem is there. Given we lack specific info for your machine, I think one method we could try is taking advantage of the heat generation. Start the machine and feel the line coming from charge pump for heat. The go to reverser lines, then line out of reverser to main pump. Basically go through the system trying to find which component has a line/lines cool coming in but warm/hot going out. Once you've gone over all the components, start over from the beginning. Logically, you'll eventually find a component thats producing heat in an output line. If you find that, you've probably found your problem area. Just a thought.
That's a good idea atco! However I've bout lost all my hydro fluid from pulling filters and reilef valves so before I fill it back up I'm gonna pull priorty valve and check the spool inside. I got some information from another website that leads me to believe I may have some issue there. But I don't think that's where all my problem is.
The priority valve is, for sure, one of the suspects. But it would have to be the relief in the priority valve. A failure of o-rings on the relief or failure of the relief that caused leakage would generate heat. Remember this, in hydraulics, resistance to flow causes two things; pressure and heat. Imagine a hydrostat dozer on a fifty mile straight push with the blade full. With every minute the dozer is pushing the load in the blade, the load is resisting oil flowing freely through the drive motors, it's taking horsepower to turn the drive motors. Therefore, the pressure is going to be high on the drive circuit because flow is being resisted. Likewise, this energy (resistance to flow) is going to create heat. Without an oil cooler, the poor thing would soon melt to the ground. Now consider this, your system is a closed center valve system. Meaning, when no functions are being operated, no oil is flowing, all oil paths are a dead end. The engine is running, the pump develops flow, but since all paths are a dead end, pressure goes up, until it reaches "standby pressure", then the pump destrokes and holds that pressure. Now, no oil is flowing, no heat is being generated. Now, lets have a failure of an o-ring that seals the relief valve in the priority valve. Now there's a very small (restrictive) passage for the oil to flow out of this closed system, and flow back to tank or wherever. The oil is now flowing, the pump strokes a bit to try and maintain the standby pressure, and the oil is flowing through a restrictive passage. You guessed it...heat. I can't say for sure that's what your machine is doing...just using logic to figure out a system that neither of us are experts about. Man I'm going to shut up for a minute.
slow hydraulics help: ATCOEQUIP... I think that was one of the finest descriptions, about the workings of a hydraulic system, I have ever read... excellent!!... :thumbsup OCR
OCR...you are killing me! I should be in bed right now...but I am having so much fun here talking to the likes of you...I'll probably be late for work in the morning! Dang you on Mountain Time! Naw...I'll get up! Thanks for the kind words.
slow hydraulics help: :thumbsup OCR
Hey bama-mill, I keep forgetting to contact my Deere dealer when I get to work. (banghead). Sent myself an email reminder to do it first of the week. But let's go over what we know about the machine. We know it's a closed center hyd circuit and should have around 2,300 lbs standby pressure on the pump output line when no functions are being operated. We know the pump has been replaced and caused no change, so it's least logical to be a pump problem. We know we are generating heat, most probable cause is internal passage of oil around a failed component or seal. All we have to do is find where the leakage is happening. First, though, have you put a pressure gauge on the pump output to verify standby pressure? Moving on, it would be nice if we knew how the fluid routes on your machine. If it's anything like the 410 circuit, fluid leaves charge pump to feed main pump (I know you've said it does a reverser connection in here, but it sounds like it's working properly), leaves main pump to feed priority valve. It goes several directions from here; loader valve, backhoe valve, steering orbit valve, aux valve (if equipped), and main pressure relief valve going back to charge pump circuit. That "relief line is the first line I would feel for getting hot. But if you don't want to take the time to wait, take this line loose from the priority valve and plug the hose fitting. It would be nice if you had a hose you could put on the priority valve fitting and drop the hose in a bucket. Start the engine, there should be no oil coming out of the priority valve fitting. Do the same to the other valves. Locate the "T" port fitting (the return line going out of valve body). Plug the hose fitting, run engine and see how much oil leaks out of the T port. A very very small amout would be acceptable, normal leakage around spools, but it should be a very small amount, not even a little stream. I know it might be a pain to do some of these valves, but you should be able to narrow down where the problem is by doing this.
Hey guys has anyone ever rebuilt the priorty valve on one of these tractors? On the inside of valve there is spool and inside of spool there is a reilef poppet, a washer\shim and a spring. I beilive this washer has become flattened somewhat and maybe binding on the inside of spool. I went to my local deere company to get a new washer and they are telling me in order to get it I've got to buy spool, poppet and washer as a kit. Has anyone ever replaced just this washer. I wouldnt think these would have to be a matched set but not for sure.
If it fixed your machine, I would go ahead an purchase the components. Don't feel bad, I needed two cartridge valves for a Komatsu D41E-6 blade control valve. A load sensing valve cartridge and a flow regulator valve cartidge. They are not sold seperately. You have got to be kidding me! Cartridge valves that aren't sold seperately! Had to purchase the whole control valve body...$3,700.00. It fixed the machine...but...ouch!
Well guys its been a rough past couple years here for my family and I so backhoe was put on hold. It's just my tinker toy. If anyone has any other ideas about this Hydraulic problem I'm all ears. Mr atco last suggestion was try to chase down heat source. Been tinkering with it here and there. Cranked up it yesterday idled it up worked all the functions for a bit and main pump, priorty valve and reverser got hot. Did about 2hrs worth of pushing dirt up then hauling it and dumping in a pile. Used the backhoe part maybe 15 minutes within the first hour out of the 2hrs. When I parked it all hydraulic parts were hot. Dipperstick and bucket cylinders, main boom cylinder all the cylinders on the loader. Main pumpwas very hot as was priority valve and reverser. Now I would expect the loader and bucket cylinders to be hotter than the ones for the backhoe because it was hardly used and not used at all for the last hour of operation. Now I said all that to setup my question. If this hydraulic system is closed center why were all the backhoe cylinders hot? How can i find the source of the heat when everything is getting hot?
I have a book in my possession that covers the B model I'll try to take a look in it tomorrow for you.
Got a look at that book tonight. I was out chasing balers tonight so I stopped by the shop and pick it up. Here's a description of the circuit diagram for S/N 161723 and later Oil is picked up from the suction screen and sent to the Transmission Oil Filter, before the filter there is a Transmission Filter Relief Valve and an Oil Cooler Relief Valve. From there the filtered oil is sent to the Front Mounted Hyd Pump and the oil cooler. High pressure oil is then sent to a Junction Block, then to an Accumulator, Pressure control valve and the Backhoe Valve. Oil from the Pressure Control Valve is then sent to Steering Valve, Brakes, Differential Lock and the Loader Valve. The oil returning from the Backhoe Valve and Loader valve is considered Low pressure oil and is routed to a Surge Relief Valve. The oil then travels to either the High Pressure pump or back to sump. Some of the Low pressure oil is also sent to the Return Oil Filter where there is another Surge Valve and a Filter Relief Valve. The pressure at the test port in the Pressure Control Valve should be 1400 psi at 1000 rpm when using a non-priority function. For a leakage test it says to run engine at 1800 rpm with hyd controls in neutral and check for heating on the return lines. If a valve within a function is leaking the line will be to hot to touch. I would do this test first thing when the machine is cold. There are other tests but they require a flow meter. I hope this helps,
Thanks for the info! When you say B model is it 310b? Does it show where the oil cooler relief valve is? I'm only seeing where the transmission filter and main pump filter relief valves are. When I had the tech manual I read about the relief valve for oil cooler but I don't remember where it is.
The way I check these things out is to start it up when everything is cool, and let it sit and idle. while it is idling, use your hand to feel the hydraulic lines,starting at the pump. follow the lines to the control valves, and the steering unit. If you have an internal leak in a valve, that valve will get hot first. The trick is do this when everything is cool. If you do it after youv'e run it a while you won't be able to isolate the problem. I have seen a few of these with bad steering valves, that act like yours.
I've been wondering about steering valve myself. Guess tomorrow I will unbolt floorboard so I can get to the valve
I have 310-A also with the same exact problems you have, don't leave me hanging, did you ever find out what the problem was? thanks
i too would like to know the final diagnosis because i have the same issues with my 310a thanks
Please feel free to start a new thread describing your symptoms and what you've done/checked/tried already. This old thread has a lot of information in it, but now the earth has cooled some, John Deere bought Van Brunt and Waterloo Boy, and Willie invented the wheel... This system isn't really as bad as it sounds, Deere designed these pumps for farmers at a time when they were still building two cylinder tractors.
Finally!! i found out what my problem was. The de-stroke valve on the main pump was the culprit. Mine would have very slow hydraulics and sometimes not at all, and you could NEVER use two functions at the same time. Just by chance i pulled the de-stroke valve out and gave it a good look. The way it works is when you crank the engine the solenoid pulls the valve back, thus bypassing hydraulic pressure to crank the engine. Well when i took mine out, inspected it and blew through the end it was not sealing back off with the plunger. After taking it apart and inspecting it i found the end of the plunger had missing pieces of steel where it was supposed to seat into end of valve, and mine was stuck partially open as i said before. After cleaning out rust and trash from valve i put it back in, no hydraulics would work then. took valve back out and it had hung wide open this time, thus explaining why i would have no hydraulic pressure at times, after beating my head against the wall for a month now, i bit the bullet and went to john deere and bought a new solenoid $261.00! ouch, but as soon as i put it in and started engine, i had instant hydraulic pressure, with multiple movements possible, works the fastest it has in years, hope this helps, good luck
Yay!!! :drinkup