Did I bust something on the loader hydraulics?

[JCoastie]

I was carrying a 16' log in my grapple and I clipped a standing tree on the left side. It wasn't crazy hard, i.e. the tires didn't come off the ground, but the left side of the tractor dove a bit. After it was over the loader was no longer level side to side, the left side was down about an inch and a half to two inches. I guess I was hopeful it'd be a bent SSQA torque tube which seems fairly straight forward to correct, but the SSQA faces are square. I can see nothing bent visibly.
Looking at the loader arms, one is definitely higher than the other. In use, It seems I can lift to max height evenly (as best I can tell) and I can press down so the implement sits flat on the ground, but I can also dig in more on the left side since it is uneven. I really don't know what's wrong. After I shutdown, I always relieve the hydraulic pressure by lowering the 3pt hitch, and the loader arms, I also toggle the loader joystick to release any remaining pressure once completely shut down. We often use the bucket top as a seat, and it's always been solid. This morning I noticed this (shutdown overnight and not started this morning), there is no pressure in the hydraulic system, all 4 rams move when I step on the bucket. Any ideas, and it is related to my uneven issue?

Video of what I am seeing New video by JCoastie

 

[ddbackhoe]

I was carrying a 16' log in my grapple and I clipped a standing tree on the left side. It wasn't crazy hard, i.e. the tires didn't come off the ground, but the left side of the tractor dove a bit. After it was over the loader was no longer level side to side, the left side was down about an inch and a half to two inches. I guess I was hopeful it'd be a bent SSQA torque tube which seems fairly straight forward to correct, but the SSQA faces are square. I can see nothing bent visibly.
Looking at the loader arms, one is definitely higher than the other. In use, It seems I can lift to max height evenly (as best I can tell) and I can press down so the implement sits flat on the ground, but I can also dig in more on the left side since it is uneven. I really don't know what's wrong. After I shutdown, I always relieve the hydraulic pressure by lowering the 3pt hitch, and the loader arms, I also toggle the loader joystick to release any remaining pressure once completely shut down. We often use the bucket top as a seat, and it's always been solid. This morning I noticed this (shutdown overnight and not started this morning), there is no pressure in the hydraulic system, all 4 rams move when I step on the bucket. Any ideas, and it is related to my uneven issue?

Video of what I am seeing New video by JCoastie

All i see is picture in the shed. I would try taking your loader off and put it back on, see if it came unseated

 

[4570Man]

I can’t view the video but check all 4 tires for even pressure before you get too carried away.

 

[JCoastie]

Tires are all even pressure. I'm new at the video thing, are you getting a specific error?
you "should" be able to click the picture in the link and the video will play.

 

[Billrog]

What's happening in the vidio is normal judt cheked mine it does the same thing. Start the tactor lift the loader let it drop a bit and lift again. Observe the loader posts on each side while doing this. See if one side moves. The metal may be tore on one side and hard to see. I had this happen once.

 

[Zebrafive]

Rather than a video, can you post pictures? My internet connection is so slow, I don't even try to load videos.
Maybe carpenter's square on the boom arm to torque tube will show if you bent the loader?

 

[Gordon Gould]

I'm no expert at all but those cylinder rams moving in and out that much look like a real problem to me. But maybe they aren't and they just appear to be the way the bucket linkage kind of covers the view.

gg

 

[Tx Jim]

Ditto what Gordon stated about too much play in bucket cylinder pistons. I'll suggest to raise FEL boom then curl/retract bucket several times utilizing tractor hyd system. If play exists then either 1 or both bucket cylinder piston seals has failed or piston has become loose from cylinder rod

 

[Billrog]

I've had 3 tractors and when the bucket is sitting on the ground with the front edge up a bit they all did exactly the same thing when you stepped on it . There is no resistance because the controls are in neutral and the fluid is able to flow with no resistance.

 

[Tx Jim]

Billrog
When FEL spool valve is in neutral position hyd fluid is designed to be trapped. If fluid isn't trapped when spool is in neutral position spool valve & housing in combination need to be replaced

 

[npalen]

Probably just a little air in the cylinders and lines.

 

[rScotty]

It looks good to me. I had a small tractor with a light bucket that the bucket would move like that when I stepped on the bucket lip, too - although my present 60 hp Kubota doesn't do that.

Anyway, If I was worried like it sounds you are I'd probably unmount and remount the bucket and maybe the loader too if it is QA. Just to satisfy myself that I wasn't overlooking something broken, bent, or just knocked out of alignment. . And then hook it all up and use it. It's probably OK, but if not, using it is unlikely to hurt anything.

 

[bdhsfz6]

I've done something similar with the FEL on one of my Kubota tractors. After going through what you are right now, I came to the conclusion that I twisted the FEL frame a bit. Since everything seemed to operate correctly, I continued to use the machine with no problems. The biggest issue was I had difficulty getting a level surface when scraping or back dragging with the bucket edge. As you noticed, it would dig in on one side more than the other.

I eventually fixed the problem by doing this: I laid a 2 X 8 on the level concrete floor of my shop. I curled the bucket down and put the cutting edge on the 2 X 8. I raised the tractor front end off the ground with the FEL hydraulics. I then loosened all the FEL frame attaching bolts a couple of turns. I did this while kneeling BESIDE the tractor and NOT underneath! I raised and lowered the front end of the tractor a few times and re tightened the FEL attachment bolts with the front end off the ground.

Using this procedure, I was able to get the bucket to within a quarter inch of level. Before, it was out more than an inch.

Again, this was on a Kubota. I don't know if it will work on your LS but it may be worth a try.

 

[Tx Jim]

Probably just a little air in the cylinders and lines.

May I ask how you think air can enter a sealed hyd system?

 

[Billrog]

Billrog
When FEL spool valve is in neutral position hyd fluid is designed to be trapped. If fluid isn't trapped when spool is in neutral position spool valve & housing in combination need to be replaced

You must be right Jim, it's just some thing I assumed since it's not be uncommon to may tractors.

 

[npalen]

May I ask how you think air can enter a sealed hyd system?

Usually via the pump.

Edit: Also, on a loader with a lot of weight and letting it down quickly and then closing the valve. The pump can't keep up.

 

[Billrog]

Well I must eat crow after Tx Jim set me straight i knew he was correct. I thought I'd better check again stepped on the bucket rocked it and sure as hell it looked like the cylinder rods moved an " or so. I knew it wasn't possible so i looked real closely where the rod came out and sure a heck it never moved. Rocking it back and forth I realized the edge of the bucket reflection on the chrome rods going up and down gave the impression they were moving. Thank you for the common sense post Jim.

 

[npalen]

C'mon guys, its very obvious that the bucket cylinder rods are extending and retracting in the video!

 

[Billrog]

Because all four rods move wouldn't that indicate something in the valve body ? How this happens when every thing functions as it should is puzzling and to boot the bucket is no longer level. Will be interesting to see the answer.

 

[Vigo327]

If the bucket not being level had anything to do with the hydraulic fluid system it would have gone away just by hitting top and bottom of lift travel a couple of times. Something is bent or shifted on that one. The fact that it goes level at the top and bottom is just the loader hydraulics flexing it back the other way, but not flexing it past its 'yield strength', so when you release it just springs back to 'bent'. With careful setup you might be able to use the loader hydraulics to 'unbend' it just like people do with their SSQA cross-tubes.

The bucket rocking so easily while the valve is in the 'neutral'/middle position likewise COULD be air but that should have rectified itself just by fully extending and retracting the cylinders several times. What makes me think it still IS air in spite of that theory, is how easily it moves. Even if a piston seal or a spool valve leaked, you still have to 'pump' fluid through that 'orifice' to get the cylinder to move, and basically ALL of the fluid in that circuit has to move to do it. Even without much restriction from the leak/orifice, it's still a fair amount of inertia and more like stirring honey than just flopping around like in that video. If you consider something like leaving the bucket tipped down a little, putting the loader in float and letting it hit the ground, turn off the tractor, and then pull the bucket curl valve, the bucket will 'settle' to the ground much slower than the movement shown in that video, and that's with the valve fully open with the whole weight of the loader and part of the weight of the bucket on it, not just something 'leaking' with one measly boot pushing down on it. The system has a LOT of air in it!

As for how the air got in there and then.. never left or never stopped reappearing, i'd be especially suspicious of shaft seals on the cylinder glands, valve body handles/levers or at the pump. A lot of hydraulic pressure seals are directional lip seals, which means their ability to seal goes up with the pressure pushing them against the shaft, and down when that pressure goes down. They're also bad at resisting any pressure from the 'outside', which is usually just atmospheric pressure so not usually a problem.

But think of this. This loader works when the tractor runs. When you pressurize circuits, it more or less becomes normal. Once you fully relieve the system pressure, it becomes wonky and may only do so after sitting for a while. My theory is that a directional lip seal is now allowing air to suck into the system when the pressure drops to 0, but then seals again as soon as you MAKE pressure in the system. I have seen something similar to this on leaky cylinder gland seals, as im sure many others have. They seal 'better' when retracting the cylinder because pressure is forcing them against the rod, but leak profusely upon extension because no real pressure builds in that chamber when the control valve is open on that side.

Just because hydraulic pressure drops to 0 doesn't mean there's nothing to generate 'suction' in the hydraulic system. The weight of any hydraulic fluid being held above the sump that has a free path to flow back to the sump is only being held in the lines by the ability of the system to keep air out of shaft seals. If you picture sticking a straw in a drink, covering the end with your finger and picking up the straw, the liquid only stays in the straw because your finger is sealing against that 'suction'. So my perhaps left field theory is that you might have damaged a directional lip seal which is allowing the weight of the fluid held above the sump to suck air into the system every time the system pressure drops to 0. The loader itself never moves because it's already on the ground, only the fluid in the system moves as some migrates back to the sump and is replaced with air. Once you start the tractor, the pressure causes damaged seal to seal again, and loader will more or less immediately work, although you might notice its initial response to the first lever inputs is delayed (squeezing the air pockets before making real pressure), and its ability to hold weight is 'springy' (air spring) until you've chased all that air back to the reservoir and purged it, at which point it becomes 'solid' again. Until it's parked for a while!