I have JD 310c Backhoe loader. While I learn how to check the hydraulic pump for pressure, wearing, being weak, or if it's flat out bad/worn/and if it's spreading metal flakes into the whole hyd. system. mean while I want to ask if this can happen, where a bad/worn hyd. pump can spread metal flakes into the hyd. fluid making the hyd. cylinders begin to leak. Because now that I just noticed I have two hyd cycl. beginning to leak... and ever since I got the machine I never did like the sound of the hydraulics, and when cold operating the buckets the unit is jittery and the system jumps as if a valve somewhere not working right, or something wrong with the hyd. pump, so I ran it a long time like that cause when it warmed up things were good... So if anybody can shed some light on this, perhaps what you've gone through I appreciate it. I forgot to mention, I took apart an old hyd. filter and didn't see anything in it, clean as can be... so now I have the hyd. filter on it now off and its ready to be cut open to see whats in it.... I hope its clean as can be with out any metallic shine... then I guess I'll be in better shape... well one thing at a time... need to see whats in the hyd filter right now... Joe
Hi Joe, you really don't have to cut filter can open. Simply remove the filter and pour oil into a clean pan, you'll see heavy metal filings if there is any. After you've drained the filter into the pan, pour some varsol, diesel fuel, or kerosene into the filter. Place somthing over the open end of the filter for a sort of lid, and agitate filter. Now pour that into a clean pan. This will wash out small filings.
is it a vane pump or a gear pump? I would not think that a pump faliure would cause a cyl leak, especially since you are not even sure if the pump is going south on you.... have you checked your suction side for any leaks? including the suction hose and pump. I have had them make noise and suck air while running but NOT leak fluid on the ground while stopped. Pj
Oh okay, I cut an old one open as if to do a comparison to the one on there now. I did what you said, I only held it upside down and watched the fluid come out both sides, no metallic or metal at all so far, I'll hit it with solvent later to make sure.... So I guess I'm in good shape, the only reason why I mentioned this was because I knew a guy that was selling his JD 410 and said his hyd. pump went bad and he said he was "told" metal went into the whole system, and this is why his steering was bad, because it wore out the spool valve where he kept needing to turn the wheel left quite a bit to just keep the machine driving straight forward. now if this was actually true who knows??? he was told to keep changing the hyd filter to catch as much metal in the hyd system, so not to cause the other cycl. to leak... oh well??? sometimes you can't believe what you hear, I've learned that the hard way...lol
I could be wrong, but I'm thinking the 310C used a gear pump, while the 410 series used a hydrostat pump. Metal in any hydo system is no good, but really bad for hydrostat pump.
Thanks... I'll have to look into what I have as far as vane or gear then get back... I've gotten to know the machine very well since I got it, but when first going into something new to fix and deal with I like to ask the experienced... So I'll see if I can find and post a view of my hyd. pump, this way making it easy to point out what to do and where to check pressure and such... Can a valve some where make a whining noise in the hyd. system? similar to a cars power steering pump being a little low on power steering fluid? Plus when I pull back not even lifting a load I hear a howl type whining sound, and its jittery cold, takes a very long time to warm up and completely stop acting jittery when lifting the arm or the loader. and the howling whining sound gets lighter when the hyd fluid gets hotter... Any idea just yet? Now that I finally got my stethoscope I'm going to listen around looking where I'm hearing noises I don't like.... thank you...
What your saying here is something I need to learn how to check, what you say sounds like this should be my problem, the sounds and noise that I just mentioned in the other post. Thanks, I'll look at the diagram where this suction side is and where it runs so to follow it...
Abnormally howling pumps are usually caused by partially plugged suction strainers. While metal flakes from damaged pumps can cause any number of problems inside a hydraulic system, they will usually get stuck in control valves before they make their way into the cylinders. You probably would have had functions getting stuck on at times. Draining the system and cleaning the suction strainer would be the first place I would go in checking out your system. A plugged suction strainer may cause cavitation and even a lack of lubrication both of which will damage the pump. The pump could also be worn and not efficient anymore which causes substantial amounts of heat. Lots of heat can cook out the rubber components of the system which always leads to leaks on hoses, seals and cylinder packing. If the suction strainer is clean I probably would consider pulling the pump for tear down to inspect the internal components. Good Luck!
I think your right on the money being gears, now that I remember reading a past repair order.... I'm going to listen to the pump today to see if any sound is coming from the hyd. pump... thank you
Depending on the serial number, the parts book shows it either has a Vickers gear pump or Sunstrand gear pump. Both have a relief valve built into the pump body. Your whine could be caused by relief valve failure or seals on relief valve failed. It's not really easy to test a gear pump for failure, because it's typically progressive. Yes, once it's experienced total meltdown pretty easy to test, but a progessively wearing gear pump is a little harder to test by simply checking pressure. Not saying it's the case, but that jittery motion, as well as the whine can be caused by excessively worn gear pump. Two things happen as a gear pump shaft bushings wear and cause gears to move to one side; metal gears will now contact pump housing, and it opens gap clearance on pressure side of gears, causes shearing of oil and cavitation of oil. If you determine the whine noise is in the area of pump, you might try taking relief out and inspecting the relief valve and its seals. If that doesn't resolve anything, you might consider removing the pump and disassemble it. Gear pumps typically give clear indications of excessive wear, and it's always better to catch one "going down" as opposed to one that totally craps out.
Thank you very much for the info.... I'd like to touch on a few things you mentioned, if you can please respond.... Is there more than one strainer? I took out the huge one in the tank, this is the tank that has the looking glass to read the fluid level, I had that one out last year and cleaned it, it was not even dirty. So far I don't believe I've ever felt a lever stick as if a valve was dirty, so thank God for that nothing felt like sticking and hanging.... but I do feel a delay with the loader operation, it's mainly felt when I'll put the loader down fast on the ground, it will pause for a moment when it touches down, then thats when I'll get a delay, when I want to lift the front wheels off the ground. I figured it was a fail safe from preventing the loader slamming into the ground and popping the front wheels off the ground in a violent manner. other than that I get the jittery operation when cold, sometimes in the Winter time it hardly goes away... thank you for all the info, I always touch the cylinders for how hot they are, and I hardly ever felt them hot, plus I don't run the machine in the hot Summer time... so with what you said I'm hoping I'm in good shape with what I know so far, at least until I check out the rest of what everybody has told me.... Thank you every one who had something to tell me, I can't thank everyone enough times, it helps me out so much when I now go outside and look it over having armed with so much good info.... Joe
Thats what I'm going to do is exactly what you said.... I've been very lucky up to this point... I believe its the original hyd pump and the machine has 9800 hours on it... I can be wrong where it can be a used one put on the machine at one time, it did come from an active construction company that may of had other machines they kept for used parts.... the pump had about an inch of gunk on it from like road grime and dust, but then I don't know anything about them just yet if its oil from the pump it self.... it does look like the original tho.... I should take it out and break it down, if I don't need any special tools to break it down I'm pretty good at finding what would be worn down out of specs... I priced a new pump from the dealer and it was around 1K, now I don't know what the best way to go on getting another pump if the hyd pump does show up no good... like where I buy one, or do I have the old one rebuilt, and how much do I focus on making sure if I get another pump that it's got to be the same specs as the one I'm taking off, then I'm worried about having any weak hyd lines popping now with a new pump if this be the case....lol geeeze....
Can I post a video? I didn't see if I can post a video of my backhoe on this forum, you'll be able to hear the sound it's making when I lift the hoe arm up being it's under load when it makes the whining noise.
I download vids to a You Tube account, then post them here. As for your pump, in most cases you can get Vickers and Sunstrand pumps from hyd parts suppliers. There are cases where the unit is made special for the OEM and you can only get it through OEM dealer.