LA525 loader rams

Fido Farms

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L3901, 35 Massey, Summit X 146, Polaris 700 RMK, Yamaha Viking
May 27, 2018
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What does this video indicate. Which at the moment I can’t load. Basically I can grab the bucket and tilt it. The rams travel about 2-3 inches before I can’t lift/tilt anymore. The loader and bucket have been sitting lifted and after a few hours I can move the bucket by hand. Is it a ram seal issue or a loader control valve issue or just normal. This is on a 2018 l3901. 150hrs. Full warranty is over in 2 weeks. The shop foreman showed me Kubota allows creep of about 2” per hour. The creep is what it is but it seems like I got a seal issue. Of course it tightens up running. If the seals r good there should be no way I can move the loader by hand? If I can move it by hand then obviously oil is passing reducing my loader capacity I’d guess. But it still lifts reasonably well. See what the thoughts are out there. Thx all
 

North Idaho Wolfman

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Load the video on Youtube then give us a link to see it. ;)
 

North Idaho Wolfman

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That is some serious air getting into it.

I don't think it's a internal seal issue, I think it's a FEL spool valve problem.
 

Fido Farms

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L3901, 35 Massey, Summit X 146, Polaris 700 RMK, Yamaha Viking
May 27, 2018
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Just wondering how the hell does air manage to get in? The rams don***8217;t seem spongy when operating. Since I was on the air idea originally I snugged all hydraulic line fittings just to make sure they good. Thx.
 

lugbolt

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ZG127S-54
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A few musings to ponder on.

Loaders have a 1 year limited warranty. They don't carry 2 years like the rest of the tractor does :(

there could be several issues there ranging from cylinder internal issues to valve issue. I lean toward cylinder issue because the valves are super simple and almost never have anything wrong with them; and when they do, it's normally caused by something else.

Is there a possibility that the loader control joystick has been sitting in a position other than neutral?
 

Fido Farms

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L3901, 35 Massey, Summit X 146, Polaris 700 RMK, Yamaha Viking
May 27, 2018
111
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Canada
Thanks for the inputs so far. If this was a ram seal issue then the loader would suck bad I think if I could move the rams that much by hand. I***8217;m thinking air in the system issue. How it***8217;s getting in there is the question. Just to be clear this just seems to be a bucket rams issue as far as I can tell so far. I know air will pass through a valve seat/connection when a fluid won***8217;t. There should be no air in the control valve unless when the machine is off it***8217;s allowing air to be sucked in a hose fitting/some other spot for air to get drawn in. Keep ur thinkin hats on. Thx.
 

lugbolt

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if it were an air issue, you would know it. 3 point hitch function would also suffer as would the loader lift function. That is usually due to leak on the suction side of the pump (between pump and transmission case including the filter). If it were a pressure side issue, you'd for sure have a fluid leak. Fluid under 2000 psi pressure is going to be much more likely to escape (violently) than air at 14.5 psi leaking "in", so I don't believe you have an air leak causing fluid aeration--unless there's more to the story that I don't know about.

I wonder if the nut that holds the piston to the ram has come off? I've seen that on some 764/765 loaders. Easy way to know. Remove the ram end from the bucket by removing the pins. Pull out on the ram(s). If it comes out of the cylinder barrel, the nut came off. At that point it's a matter of removing the gland and retrieving the parts inside then installing them in the proper orientation. I've seen a few over the years with loose hardware, rarely completely off but that's happened too.
 

North Idaho Wolfman

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lugbolt might be onto something, because the cylinders are used in tandem, one piston being damaged could cause some weird effects.

Do like he said and pull the pins and see if one cylinder reacts different than the other when they are not hooked to the bucket.
 

PoTreeBoy

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To summarize first, I don't think you need to be concerned if the drift is within Kubota's allowance.
Could be a valve leak, but if so it's on the rod side only. If it was on the cap side, fluid would leak in and prevent moving the bucket. Some of the sections on my backhoe have anti-cavitation checks which accomplish this. I don't know how Kubota determines where these are needed and where they're not.
Anyway, I think what you're seeing is not air but a vacuum void. The weight of the bucket is trying to extend the cylinder(s). A slight leakage allows fluid to flow from the rod side of the piston to the cap side. But the volume (area) on the cap side is larger, so there is not enough fluid available to fill that side as the piston moves, so a void (vacuum) forms.

This link (if I've done it right) explains it better:
https://www.machinerylubrication.com/Read/1119/hydraulic-cylinder-drift
If we always did what the manual (and safety) says :rolleyes: and lowered all attachments when shutting down, we'd never notice this effect.
 
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Fido Farms

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Equipment
L3901, 35 Massey, Summit X 146, Polaris 700 RMK, Yamaha Viking
May 27, 2018
111
5
18
Canada
Thanks for the ideas. I believe Po is correct on the vacuum/seal seepage. I did remove the rams too and both behave like they should. There is a test for this by unhooking one cylinder line and applying pressure to the other and see if the ram moves. I may try that another time. As far as I can see no real issue at the moment unless the loader starts struggling and I may need to peek at the seals. Thanks again for the input