Backhoe Loader John Deere SN T0310SJ148669 Kind of think I need to find a manual for this machine, but here is the problem. Cranks and runs fine. F-N-R movement fine. Zero hydraulics on bucket, stabs, and boom assembly. Steering has no assist. First exam was to see that there was virtually no hydraulic oil in the reservoir. Added 10 gallons, it's on the sight tube. Still nothing on the hydraulic system. We have a matched pair, so can do some comparisons. Parking brake switch does indeed kill all drive. Still no hydraulics. Assuming the steering runs off the same pump, it seems to point to a pump problem. Reasonable to tee into the main pump output line to check for pressure or is there a more obvious visual test? The enable switches appear to work, at least indicating active hoe, or active motion. At least the indicator lamps light up. It failed in the field suddenly. Was lifted and chained up for transport, and I was able to drive it into the shop. Like to have some plan for Monday to see if I can find the problem. I've not worked on a 310SJ before this. I don't have the ops manual, so could be overlooking a selector switch,but the operator on it when it failed is experienced, so I'm thinking it isn't just something I've overlooked. I have run and worked on a few other BHL's. Suggested actions?
First check pressure at location shown below. If no pressure cut open and inspect the filter. If there is metal (and even if there is no metal), then I bet the shaft in the second picture is broken, usually due to a seized pump.
I worked a lot on the G series. I’d check the pump pressure. If the pump seized solid I’ve seen to take the drive out of the tc. It’s a long thin shaft that runs through the transmission. Again that’s a G
Thanks mg....if the pump has seized, and broken that shaft, that looks like a painful repair. That's kind of what I was afraid the case would be. I'll get some adapters from Axxion for the gauge collection I am accumulating if I need to. Have an idea what the pressure would be at idle, and/or at operating speed? What am I looking to see? Thanks Mike. Since I can still move the machine, wouldn't that indicate that the tc was still alive? If that shaft is broken, I can see the pump drive fail, obviously, but if it twisted the shaft early enough, as in before overloading the tc, might it survive?
The last one I did took some of the drive teeth of the tc and the shaft. The shaft doesn’t drive any transmission stuff so it still drove just no hydraulics.
Well Mike, it would appear some teardown is likely in my future. If the pressure is not there, I'll figure that the pump is the culprit and do whatever it takes to see about that pump drive shaft. If it's indeed twisted and broken, then it's a safe bet the pump is seized and depending on the condition of the tc end of that shaft, whether there is damage there as well. Doesn't sound like much fun to me. Glad I have some young strong help.
3525-3725 psi @ fast idle. When checking the pressure, check with a backhoe function first, then a loader function next. I say that because I see your machine is pilot controlled. If your pilots are dead then the hoe won't have any pressure, but your loader is mechanical linkage so if there is any life left in the pump some sort of pressure should be seen. And that shaft can break without ruining the torque converter.
Yes I didn’t want to sound all doom and gloom. Just another thing to check. if you diagnose a bad pump and install a new one and it still has no functions usually leads to more time testing and retesting. Easier to check if you do end up removing the pump
Thanks mg. I haven't looked for a manual yet, so I don't have any specs to refer to. I may tap a pilot line, if I can find an accessible spot, to see if I even have pilot pressure. The way I was told it failed, suddenly went from normal to zero hydraulics sure makes me suspect the pump, but I won't go into this with any preconceptions. That can get to be a mental trap. So I start with basic tests and no assumptions. Mike, I didn't take it that way. I appreciate you pointing out possible failures. It gives me more to look for as I get into this thing.
I got the manuals. PM me.
Thank you, mneagle. Those will help.
mg, just letting you know that I located the test port, already with a dry-break connector. As usual though, got pulled in another direction. Had a Komptech service guy out from N.C. to see why there was a bundle of original wires just chopped and laying loose in the control panel on my Crambo 5000. Turns out that the previous owner (a municipality) had been working on it, probably the same thing I'm trying to fix, and replaced a lot of signal wire but left the old. So far I'm stuck, because there are problems with the membrane switches on the panel. Komptech had one on the shelf but it is bad, so they are looking for another. Machine comes from Austria, and the part may have to come from there, at who know what price and lead time. Only then will I be able to see if the hacks did their job, or there are more problems. They used an incorrect crimp tool for the inserts in the connector blocks on the relay board and it failed the wiggle test, so I get to rework those. Probably 35-40 terminals. Anyway, I have a couple of pumps to go through on our Diamond Z that burned before the engine guys can even start the engine. I hope they aren't roasted too badly. It's always something. At least I can't say it's boring, never done the same thing twice yet here. I'll post my pressure test results as soon as I get them. I' still thinking zero, and thinking back, even being near deaf, there is a very unhealthy sound coming from the general area in front of the pump. Pump looks sort of a not so easy job to pull, so I may delegate that part to the young guns in the truck shop. Anyone rebuild those, or are they more commonly just replaced?
If it is toasted, replace it.
Yeah, I didn't realize it was a gear pump until I looked in the manual. Not planning on rebuilding.
We need to hire a narrator and a music person to add suspense like they do on that Gold Rush reality program.
One of our older hands suggested looking first at what he called a priority valve, something that gives the steering system pressure regardless of the cylinders for the loader and hoe. Sort of makes sense, because even if you lose those systems you still should be able to steer the machine. He was not very clear about it though. Said it was an electrical solenoid valve located at the pump inlet. Any thoughts on that, or whether it could cause loss of pressure. When I moved the machine, I did have some steering, so it makes me wonder if there is something worth checking on that valve or not, and whether it can be tested safely while in place. My keyboard is failing, so pardon the lack of proper punctuation. The p in particular has failed. I had to use charmap and copy and paste to get it here at all. Guess I'll move to another computer until I resolve that.
If you have any steering and no hydraulics the priority valve is probably stuck. Most likely from debris from a grenaded hydraulic pump. The priority valve is where the oil enters the backhoe valve. That solenoid on the pump is for the unloading circuit. Seat forward and the little pump on the back of the hydraulic pump just circulates oil within itself so you have more available engine horsepower for loader operations. Seat in the backhoe position and the little hydraulic pump supplies more oil flow for backhoe for faster cycle times.
There is some steering. Since there is no mechanical steering, the fact that it has any tells me there has to be some pressure available. But it was difficult to turn the wheel and I could only make wide turns to get it where I needed to. I guess if I drop the spool from the priority valve and see if it is indeed stuck and find any debris. If it were stuck slightly out of position I suppose I'd have some steering pressure but no normal, which is what it feels like, or air in the system. A quick and dirty check would be to break a hose loose and activate a cylinder and see if I get flow. Then go backwards to the pump and see what is there. I think I'll get on this today, after sorting out the pump system on the burned grinder. It doesn't look bad at all. Seals and gaskets are fine. Only damage is a couple of solenoids and their connectors. Those melted off. This thing was only burning a few minutes, and I don't think the pump(s) got all that hot. But when I show up, who knows what else will be down. But if I can I'd like to settle this backhoe. We have a twin outside with some other problem right on its heels. So while I have the books out I may as well drag it in. Not sure what the complaint is on it. Weird....the keyboard is acting normal this morning. Think I'll order one anyway. That or buy myself a new lapie. I found a source of off-lease ToughBooks. Love those things.
With no hydraulic pressure you will still have steering. There is a little pump inside the orbital valve that will move enough oil to give you difficult steering. Did you cut open the filter yet?
No on the filter. Missed my chance on that. I believe they swapped in the field and it got dumped. So, tell me about the hydraulics enable switch up on the dash. I have no power to it, the old guy said should have battery power there. He said that locks the entire hydraulic system. I assume he means sends it to bypass back the the tank. Two wires, red and green. No power on red, 25meg or so on the (I guess) the coil side. All fuses good. I supplied 12 to it, and still nothing. So if this is related, the coil seems pretty high, but I have no specs, so can't condemn it yet. There has been some minor hackage to the electrics but not much. But if he's right, and there are no other enable/disable devices, then I have to suspect the solenoid that it operates. The test port that you (mg) pointed out, has no pressure no matter what I do. Switch in circuit and on, power supplied from elsewhere, nothing. I'm not sure I could hear that solenoid even without the engine running so can't say whether is it moving the spool or not. I suspect not. I can attempt to power it right at the valve, but I don't expect anything different. It seems to be coming down to something locking out the valve body electrically, or a bad pump/broken shaft. I wish they would provide a shutoff for the reservoir. I think I may pull the pump, unless there is some other aspect I need to look at first. I didn't get much time on it today. As usual, before 0700 there were 3 other machines down. Bad part for me is that I don't get those calls until our truck guys have a go at it usually. At least one was simple, but bothers me. The Volvo 250 popped up a anti-theft warning and stopped. I just d/c the batteries and waited a few minutes and it reset, ran the rest of the day. Some day, it's not going to be so simple. It throws ghost codes a few times a week. Do we have a Wanted section on this forum? Need an impossible part.
The pilot enable switch is on the right backhoe lever tower and is on pilot operated machines only which I see yours is. It will only disable the backhoe functions, not the loader functions. Lets back up and clarify. Do you have no loader and backhoe functions at all or do you have loader functions and not backhoe functions? I though you indicated no hydraulics at all. If that includes testing the loader function then we are back to the drive shaft/pump issue.
mg, this toggle switch is up on the flat(ish)panel "behind" the steering wheel. It is yellow, and must be pushed in to lock. The only symbols are an open and a closed padlock. I'm only calling it related to the hydraulics because of what the old hand told me. He's come through working at at least Case and Deere dealers, so I figure he's probably right. I didn't take any pics. I know the switch you are referring to, and I'm talking about a different one. The switch you mentioned does seem to function, electrically at least, because I do get an indicator (green light) on the main control panel. Has no other effect, however. It concerns me that I do not have battery voltage at the switch on the dash, yet all fuses are good and even supplying it via jumper, I still get nothing. If it is the pump/shaft that would be the case though. I'll still need to fix that, regardless. I have not spotted it, but I suppose someone could have taken that switch out of circuit and wired it direct. It would explain the lack of power to it, and depending on exactly what they did, the resistance to ground I am reading. Although, if it were wired up as powered all the time, and still connected to the coil I would have a few volts there on the coil wire, allowing for voltage drop through the coil. I have no voltage on either wire. I have no loader and no digger functions, nor can I operate the stabilizers. So I'd have to say no hydraulics at all. I tested with engine speed up, pilot enable switch on, and get no digger, regardless of the lockout switch. And no pressure. In any case, the stabs should work if the hydraulics were pressured up. That I suspect would be about a basic a circuit as possible.
That is for operating the front bucket coupler. Since you have zero pressure, time to pull the pump and the pump drive shaft.
Get your tools out Tony! Take pics too as you go! LOL
I may set up my video cam and record the mess I make just draining the oil. I think we have a filter cart now, so perhaps I can empty the reservoir with it into some clean containers rather than just dump it into a drain pan. Guess it's come to that, so I'll be on a creeper Monday lol. They could have at least put an isolation valve at the reservoir. But, they didn't so I'll just try to minimize the mess. At least it is supposed to be pleasant weather, temp wise so as long as I am inside, I will do it. It does not appear to me a difficult pull at least. Thanks for the help! Will keep this alive to the end.