I am having hydraulic problems with a, model year 2000, John Deere 410e 4x4, without EXT. Hoe. The backhoe is new to me(just purchased). I knew it had a faulty orbital/priority steering valve before purchasing it. I imediately bought, and replaced it with a brand new setup. Prior to replacing the steering valve the tractor had/has excessive main pump pressure at all times. The machines hydraulics all work, but its like a relief valve is stuck somewhere. At idle the main pump is pushing around 1200 PSI without touching a single control. That seems like to much to me. when using any of the hydraulics, and the boom, bucket, steering, etc, etc reach full stroke it almost kills the engine on the tractor. Any suggestions from you experts?
Welcome to the forum johnny_waz. I moved your post to a new thread hoping it will attract some comments. That's a variable displacement, load sensing hyd system on that machine. I'm not sure what the stand by pressure should be on that system, but if you work any function and it nearly kills engine from load then there's something wrong with pump. I've never worked on that model machine, nor that pump, so I can't offer any advice. It will most likely require having someone with knowledge of that system to repair it, or remove the pump and send it to a pump shop to be tested and repaired as needed.
Thanks for moving it for me willie59. This new load sensing system I fear is going to be the death of me. I have the repair, and technical manuals on their way to my house, but I won't get them till next Wednesday. Hence the reason I am posting here trying to get a head start. I'm hopeing someone else here encountered the same problem at some point. This backhoe has an adjustable, load sense module, and an adjustable pump flow limiter all attached to the main pump. I can tell by looking at them that the adjustments have been fiddled with(wrench marks). If I was a gambling man I would say the the pump flow limiter is out of adjustment. Cause like I said, the entire machine has good hydraulic movements, and power. But when you go full lock on ANY hydraulic movement it almost stalls the motor. It acts like a relief valve is not opening. If the backhoe or front loader is operated for more than 5-10 minutes non stop the hydraulic lines get so hot you can barely touch them. Only had this new hoe 1 week, and i'm already missing my trusty john deere 310 hoe I traded in for this newer 410e.
I'm no mechanic but I do know these systems rely heavily on a network of resolvers. I've had problems in the past and the seals at the base of the resolvers were the culprit (not the same machine but also a closed centered, load sensing, variable piston pump). Older machines tend to have more problems with the o-rings as they get brittle, and stiff, with age and repeated heating cycles. It sounds to me like the pump is not de-stroking. The system senses demand through a signaling circuit so my thinking is that the pump is being told that the system needs oil when, in fact, it doesn't. In this hypothesis the engine will bog because it is trying to pump oil that has nowhere to go. It sounds like you already have the pressure, and I assume flow, gauges so you should be able to follow trouble shooting as it is laid out in the repair manuals that you are expecting. This should also reveal the stand-by pressure but I suspect hat 1200psi is not out of line.
Relax johnny, load sense systems aren't really a bad thing, it's actually an excellent system that provides precision control one moment, then full tilt operation the next moment. I think DGODGR is right that pump is not de-stroking. I can't say this is [exactly] how your system works, but the basics of load sensing hydraulics is a simple concept. It all revolves around "stand by" pressure, the load sensing system is looking for changes is this pressure (demand). This is typically done by using a variable displacement pump, and closed center hydraulic system. When the pump is turning, it's moving oil (output). Oil goes out the output line to the various control valves. All the valves/components are "closed center", meaning they are a hyd dead end. Given that, pressure builds. At the point determined "stand by" pressure is reached, load sensing system "de-strokes" the pump output by changing the position of the pistons inside the pump. This stand by pressure on pump output line is maintained when no functions are being operated. Stand by pressure can be whatever the designer desires. I seen some systems that stand by is as low as 300 psi, others at 2,000 psi. The number only matters in that it's set at what mfg recommends, that's the first thing that needs to be checked. The next aspect of load sensing is pump control when functions are operated, reaction of pump, which is likely where your problem is. Let's say your stand by should be at 500 psi. What that means is the pump control system (load sense) is always trying to keep pump outlet line at 500 psi more than what is being demanded. Engine running, no functions operated, pump output would be at 500 psi. Now operate a function, lift loader arms, that requires 300 psi to move function. As soon as you operate loader valve, pressure on pump output drops, pump compensator reacts and changes pump output to required demand, which is 500 psi stand by and the additional 300 psi needed to lift loader, total 800 psi. The pump compensator is always trying to maintain the 500 psi plus whatever psi is required to operate a function. The point is to only supply output (gpm and pressure) of pump to match demand. In your case, it sounds like your pump is delivering more than is demanded. The result would be if you totally stabbed the lever in to lift loader arms, it would likely work ok, maybe load the engine a bit, but not stall it. However, just feather the loader valve open a bit to slowly lift loader arms, metering oil through control valve, the pump is putting out more than is demanded, too much pressure and too much gpm output being crammed through a restricted opening at valve spool. Result; engine loading and heated oil. It sounds to me you have a problem in the control system of your pump. Exactly what it is and how to fix it, don't have any experience with that unit. I hope you find a resolution to your problem.
You have me wondering on the O-ring thing. Today after I changed all the filters on the machine I fired it back up and ran it for about 5 minutes. After I shut it off and climbed down I could hear a slight hissing sound of air being drawn in or let out somewhere near the pump. You got me wondering about an O-ring now. I will have a helper tomorrow to fiddle with the machine. So I will see if I can track down where the hissing sound is coming from. I have to work on the machine outside, and it was raining today so I gave up early. Tomorrow I won't give up as easily. I'm sure I am going to sound stupid here, but can you describe what a resolver is, or looks like?
That is 100% EXACTLY what happens! Even in the order you describe.
Well, I'm not a liberty to use the term "exactly" johnny as I'm simply commenting via internet, but from what you've described, sounds like you pump control has flipped out.
Johnny, See if you can come up with the model code for the pump, the load sense system is a good control method and nothing new, been around since about 1969. In heavy industry a load sense control will always be run in parallel with a compensator, from your description in your first posting where the engine stalls when you bottom out a cylinder-that sounds like a compensator set higher than the relief valve so your pump would not de-stroke. Tom
The pump is an, OILGEAR, AT191574.
Maytag, is there any O-rings on the relief valve that could fail which would cause the, compensator to now be higher in pressure? This is of course assumeing everything is currently adjusted correctly.
oilgear I tried to post an Oilgear example of how to break a model code down-exceeded the host limit. anyway you can go to the Oilgear site, you should have something like a PVV or PVG model-the numbers only you furnished don't translate into a model code, maybe Mother Deere had Oilgear private label for them-
Just wanted to post back and tell everyone thanks for all your knowledge. My manuals came, and I was finally able to figure out what was going on with my machine. DGODGR was right, it was an O-ring! An O-ring had gone missing (probably sucked into system) inside 1 of the load sense blocks bolted to the side of the main pump. It was only 3 bolts to removed the entire load sense assembly off the side of the main pump. I was able to take it off the pump without removing the pump from the machine. Inside the assembly of load sense blocks (3 blocks bolted together) were a series of O-rings, and 2 gaskets. All were replaced, and the machine performs flawlessly now. Parts cost me less than $30.
Here is a picture of my new to me baby.
Good to hear you got it sorted out Johnny_waz. :drinkup
Thats a nice clean looking Deere Johnny_was Planning to repaint my old 310D this fall. Hope it looks that good when done.
Ya, it is VERY clean. That is why for $19,500 I could not pass it up. I only have another $988 in parts into it to make it %100 machine. Came with 3 quick change rear buckets to, 18", 24", 30".