ala.millwright
Well-Known Member
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.
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310a slow hydraulics help
- Thread starter ala.millwright
- Start date
willie59
Administrator
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?
ala.millwright
Well-Known Member
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.
willie59
Administrator
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?
ala.millwright
Well-Known Member
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!!
ala.millwright
Well-Known Member
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.
ala.millwright
Well-Known Member
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.
ala.millwright
Well-Known Member
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?
willie59
Administrator
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.
ala.millwright
Well-Known Member
Okay that would be great!!
willie59
Administrator
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?
bill onthehill
Senior Member
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.
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ala.millwright
Well-Known Member
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.
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willie59
Administrator
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.
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ala.millwright
Well-Known Member
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.
bentwrench22
Member
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
willie59
Administrator
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.
willie59
Administrator
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.